Systems and methods for analysis of biological fluids

Abstract

In some embodiments, fluidic devices provided herein comprise one or more layers (e.g., a first layer) comprising a porous material. In some embodiments, the device comprises a first layer comprising two or more sample receptions regions (e.g., a first sample reception region and a second sample reception region) wherein the sample reception regions are in fluidic communication with each other through a channel. In some embodiments, the first sample reception region is configured to receive a fluid (e.g., a sample) comprising white blood cells and red blood cells. The porous material, configured to retain at least a portion of the white blood cells and allow the transport of at least a portion of the red blood cells, may allow for the fluid to flow through the fluidic device such that the second sample reception region is enriched with red blood cells.

Description

[0001]SYSTEMS AND METHODS FOR ANALYSIS OF BIOLOGICAL FLUIDS RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 519,224, filed August 11th, 2023, and entitled “SYSTEMS AND METHODS FOR ANALYSIS OF BIOLOGICAL FLUIDS,” and U.S. Provisional Patent Application No. 63 / 663,009, filed June 21st, 2024, and entitled “SYSTEMS AND METHODS FOR ANALYSIS OF BIOLOGICAL FLUIDS,” which are incorporated herein by reference in their entirety for all purposes. TECHNICAL FIELD Fluidic devices comprising porous materials are generally described. SUMMARY Fluidic devices comprising porous materials are generally described. The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles. Some aspects of the present disclosure relate to fluidic devices. In some embodiments, the fluidic device comprises a first layer comprising a porous material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region; and wherein, upon application of a fluid comprising white blood cells and red blood cells to the first sample reception region, the porous material is configured to retain at least 75% of white blood cells upstream from the second sample reception region and allow transport of the red blood cells to the second sample reception region via the channel. In some embodiments, the fluidic device comprises a first layer comprising a porous material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region; and wherein, upon application of a fluid comprising white blood cells and pathogens to the first sample reception region, the porous material is configured to retain at least 75% of white blood cells upstream from the second sample reception region and allow transport of the pathogens to the second sample reception region via the channel. In some embodiments, the fluidic device comprises a first layer comprising a porous material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region, wherein: the second sample reception region is positioned along the channel greater than or equal to 10 mm away and less than or equal to 30 mm from the first sample reception region, the channel has a length greater than or equal to 10 mm and less than or equal to 42 mm, the channel has a thickness greater than or equal to 0.4 mm and less than or equal to 0.8 mm, the channel has a width greater than or equal to 2 mm and less than or equal to 10 mm, and the channel has a porosity greater than or equal to 50 and less than or equal to 90%. In some embodiments, the fluidic device comprises a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region; and a second layer, wherein the second layer comprises a vertical transport region in fluidic communication with the first sample reception region and the second sample reception region, and wherein the first layer and / or the second layer comprises a nucleic acid stabilizer. In some embodiments, the fluidic device comprises a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, wherein the channel places the first sample reception region in fluidic communication with the second sample reception region, and wherein the first layer comprises a nucleic acid stabilizer. In some embodiments, the fluidic device comprises a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, wherein the channel places the first sample reception region in fluidic communication with the second sample reception region, and wherein the porous, absorbent material is configured to transport red blood cells therethrough to a higher degree than white blood cells. In some embodiments, the fluidic device comprises a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region; and a second layer, wherein the second layer comprises a vertical transport region in fluidic communication with the first sample reception region and the second sample reception region, and wherein the first layer and / or the second layer comprises an RNA stabilizer. In some embodiments, the fluidic device comprises a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, wherein the channel places the first sample reception region in fluidic communication with the second sample reception region, and wherein the first layer comprises an RNA stabilizer. Some aspects relate to methods of determining a property of a blood sample. In some embodiments, the method comprises transporting a fluid comprising white blood cells and red blood cells through a channel from a first sample reception region to a second sample reception region, wherein at least 75% of the white blood cells are retained upstream from the second sample reception region and a portion of the red blood cells is retained in or on the second sample reception region. In some embodiments, the method comprises transporting a fluid comprising white blood cells and pathogens through a channel from a first sample reception region to a second sample reception region, wherein at least 75% of the white blood cells are retained upstream from the second sample reception region and a portion of the pathogens is retained in or on the second sample reception region. In some embodiments, the method comprises transporting a fluid comprising white blood cells and red blood cells through a channel from a first sample reception region to a second sample reception region, wherein: the second sample reception region is positioned along the channel greater than or equal to 10 mm away and less than or equal to 30 mm from the first sample reception region, the channel has a length greater than or equal to 0.1 mm and less than or equal to 42 mm, the channel has a thickness greater than or equal to 0.4 mm and less than or equal to 0.8 mm, the channel has a width greater than or equal to 2 mm and less than or equal to 10 mm, and the channel has a porosity greater than or equal to 50 and less than or equal to 90%. In some embodiments, the method comprises transporting a blood sample comprising a plurality of white blood cells and a plurality of red blood cells through a fluidic device to a first region and a second region, wherein the second region is a sample reception region, wherein at least a first portion of the fluid is retained in or on the first region and a second portion of the fluid is retained in or on the second region, wherein the first portion of the fluid is enriched in white blood cells, and wherein the second portion of the fluid is enriched in red blood cells; and assaying the first region or the second region. Some aspects relate to methods of determining a bloodborne pathogen. In some embodiments, the method comprises transporting a fluid comprising a plurality of white blood cells and a plurality of red blood cells through a fluidic device to a first region and a second region, wherein the second region is a sample reception region, wherein at least a first portion of the fluid is retained in or on the first region and a second portion of the fluid is retained in or on the second region, wherein the first portion of the fluid is enriched in white blood cells, and wherein the second portion of the fluid is enriched in red blood cells; and assaying the first region or the second region for the bloodborne pathogen. Some aspects relate to methods. In some embodiments, the method comprises laterally transporting a fluid comprising a plurality of cells through a channel, wherein: the channel is positioned in a first layer comprising a porous, absorbent material, the first layer further comprises a first sample reception region and a second sample reception region, the channel places the first sample reception region in fluidic communication with the second sample reception region, and the first layer comprises an RNA stabilizer. In some embodiments, the method comprises laterally transporting a fluid comprising a plurality of cells through a channel, wherein: the channel is positioned in a first layer comprising a porous, absorbent material, the first layer further comprises a first sample reception region and a second sample reception region, the channel places the first sample reception region in fluidic communication with the second sample reception region, and the first layer comprises a nucleic acid stabilizer. Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the disclosure when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control. BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures: FIG. 1A is a schematic showing a cross-section of a fluidic device, according to some embodiments. FIG. 1B is a schematic showing a plan view of a fluidic device, according to some embodiments. FIG. 1C is a schematic showing a plan view of a fluidic device comprising a channel extending beyond a second sample reception region, according to some embodiments. FIG. 2A is a schematic showing a cross-section of a fluidic device comprising two layers, according to some embodiments. FIG. 2B is a schematic showing a cross-section of a fluidic device comprising two layers, according to some embodiments. FIG. 3 is a schematic showing a cross-section of fluidic device comprising three layers, according to some embodiments. FIG. 4 is a diagram showing DBS cards for collection and enrichment of Plasmodium nucleic acids in infected RBCs (iRBC) by depletion of host WBCs, wherein Whatman 903 cards (left) offer negligible cell separation, while pDBS cards with either 1 (middle) or 2 layers (right) of Leukosorb substantially purify iRBCs, according to some embodiments. FIG. 5 is a plot showing relatively successful amplification of P. falciparum RNA isolated from punches of pDBS cards, according to some embodiments. FIG. 6A is a diagram depicting renderings of device pre- and post-sample addition showing the multi-layer, multi-material design containing white blood cell-depleting inlet zone (arrow) and channel, as well as an outlet zone that can be excised for downstream analysis, according to some embodiments. FIG. 6B is an image of a fluidic device, according to some embodiments. FIG. 7 is a qualitative analysis of an exemplary fluidic device to assess white blood cell depletion wherein white blood cells were isolated, stained with DiI, returned to (a) buffer or (b) whole blood, and analyzed using a fluorescence microscope and wherein white blood cells in buffer and in whole blood were depleted from the sample as the sample wicked along the device, according to some embodiments. FIG. 8 depicts data related to qPCR quantification (CT value) of human 18s rRNA (leukocyte) target, according to some embodiments. FIG. 9 depicts data related to ΔCTValues (CTdevice– CTwhole blood) human 18s rRNA (leukocyte) target, according to some embodiments. FIG. 10 depicts data related to the preparation of various parasitemia ranges using synchronized culture and whole blood, according to some embodiments. FIG. 11A depicts a rendering of card prototype 1 with a two-layer design: a bottom layer of wax-patterned TFN channel and a top layer with a 7 mm TFN circle, according to some embodiments. FIG. 11B depicts a scanned image of prototype 1, according to some embodiments. FIG. 11C depicts filling across 25–55% hematocrit of prototype 1 having a 6 mm punch zone denoted by the arrow, according to some embodiments. FIG. 11D depicts an analysis of punch zone volume (N = 3 punches per hematocrit) across hematocrits determined using Drabkin’s assay where the solid line parallel to and spanning the length of the x-axis represents average punch volume and the dotted lines represent 95% Cl., according to some embodiments. FIG. 12A depicts a rendering of prototype 2 with a two-layer design: a bottom layer of wax-patterned TFN channel and a top layer with a 7 mm Leukosorb circle, according to some embodiments. FIG. 12B is an image of prototype 2, according to some embodiments. FIG. 12C depicts filling across 25–55% hematocrit of prototype 2 having a 6 mm punch zone is denoted by the arrow, according to some embodiments. FIG. 12D depicts an analysis of punch zone volume (N = 3 punches per hematocrit) across hematocrits determined using Drabkin’s assay where the solid line parallel to and spanning the length of the x-axis represents average punch volume and the dotted lines represent 95% Cl., according to some embodiments. FIG. 13A depicts a rendering of prototype 3 with a three-layer design: a bottom layer of wax-patterned TFN channel and two top layers with 7 mm Leukosorb circles, according to some embodiments. FIG. 13B is an image of prototype 3, according to some embodiments. FIG. 13C depicts filling across 25–55% hematocrit of prototype 3 having a 6 mm punch zone is denoted by the arrow, according to some embodiments. FIG. 13D depicts an analysis of punch zone volume (N = 3 punches per hematocrit) across hematocrits determined using Drabkin’s assay where the solid line parallel to and spanning the length of the x-axis represents average punch volume and the dotted lines represent 95% Cl., according to some embodiments. FIG. 14A depicts a rendering of prototype 4 with a laser cut, single layer Leukosorb channel, according to some embodiments. FIG. 14B is an image of prototype 4, according to some embodiments. FIG. 14C depicts filling across 25–55% hematocrit of prototype 3 having a 6 mm punch zone is denoted by the arrow, according to some embodiments. FIG. 14D depicts an analysis of punch zone volume (N = 3 punches per hematocrit) across hematocrits determined using Drabkin’s assay where the solid line parallel to and spanning the length of the x-axis represents average punch volume and the dotted lines represent 95% Cl., according to some embodiments. FIG. 15 depicts data related to the analysis of Punch Volume using Drabkin’s Assay, according to some embodiments. FIG. 16A depicts a plot representing amplification curves for human β-actin and Plasmodium sbp1 genes, according to some embodiments. FIG. 16B depicts a plot representing melt curves for human β-actin and Plasmodium sbp1 genes, according to some embodiments. FIG. 17 depicts data related to an analysis of WBC Depletion from 903 Card, Prototype 3, and Prototype 4 (LDC), using B-actin, according to some embodiments. FIG. 18 depicts data related to raw Ct and calculated ΔCts, ΔΔCts, and fold change for in vitro contrived samples, according to some embodiments. FIG. 19A is a box plot depicting in vitro parasite enrichment (fold change) from samples made using contrived blood from a single, infected donor wherein each data set represents five parasitemias (0.001, 0.01, 0.1, 1, and 5%, N = 5 replicates per parasitemia for a total of 25 measurements), the box represents 25th–75th percentiles, the y-axis has been log-transformed for clarity, the middle line represents median value, the whiskers represent 5–95% percentiles, and visualized data points represent values (2 / 25 points per comparison) falling outside of the 5– 95% percentiles, according to some embodiments. FIG. 19B is a box plot depicting clinical parasite enrichment (fold change) from samples made using malaria-infected patient samples wherein each data set represents 16 patients (N = 3 replicates per patient for a total of 48 measurements), box represents 25th–75th percentiles, y- axis has been log-transformed for clarity, middle line represents median value, whiskers represent 5–95% percentiles, and visualized data points represent values (4 / 48 points per comparison) falling outside of the 5–95% percentiles, according to some embodiments. FIG. 20 depict data related to patient demographics of clinical study population in order of ascending parasite count, according to some embodiments. FIG. 21 depict scan images of Whatman 903 Protein Saver Cards from clinical patients 01–16 wherein 50 µL venous blood was added to each spot by pipette, according to some embodiments. FIG. 22 depicts scan images LDCs from clinical patients 01–16. 50 µL venous blood was added to each inlet zone by pipette, according to some embodiments. FIG. 23 depicts data related to uncorrected Ct values for clinical samples in order of ascending parasite count. according to some embodiments. FIG. 24 depicts data related to corrected Cts for clinical samples in order of ascending parasite count, according to some embodiments. FIG. 25 depicts data related to ΔCts and ΔΔCts using corrected Ct values, according to some embodiments. FIG. 26A is a plot depicting Sbp1 Ct as a function of parasite count for a 903 card using in vitro (n = 5 parasitemias, N = 5 replicates per parasitemia) and clinical samples (n = 15 donors, N = 3 replicates per donor), according to some embodiments. FIG. 26B is a plot depicting Sbp1 Ct as a function of parasite count for a LDC using in vitro (n = 5 parasitemias, N = 5 replicates per parasitemia) and clinical samples (n = 15 donors, N = 3 replicates per donor), according to some embodiments. FIG. 26C depicts data related to an analysis of covariance (ANCOVA) of linear regressions, according to some embodiments. FIG. 27 depicts data related to fold change values for clinical samples using corrected Ct values, according to some embodiments. FIG. 28A is a plot describing liquid calibration curves for WBC counts obtained using a serially diluted WBC sample from a healthy patient (N = 3 replicates per count) wherein the data was fit using a linear regression (Slope = -3.129, Efficiency = 109%), according to some embodiments. FIG. 28B is a plot describing liquid calibration curves for parasite counts obtained using a serially diluted liquid clinical sample (N = 3 replicates per count) wherein the data was fit using a linear regression (Slope = -3.395, Efficiency = 97%), according to some embodiments. FIG. 29 clinical WBC and parasite count from 903 Cards, LDC, and liquid references, according to some embodiments. FIG. 30 depicts data related to clinical WBC recovery from 903 Card and LDC, according to some embodiments. FIG. 31 depicts data related to clinical parasite recovery from 903 Card and LDC, according to some embodiments. FIG. 32 depicts data related to clinical WBC and parasite recovery from 903 Card and LDC, according to some embodiments. FIG. 33A is a plot depicting sample read count from Illumina sequencing as a function of parasites μL-1 wherein patients 09, 02, and 11 were analyzed to cover a wide range of parasite counts (* p < 0.05, ** p < 0.01, *** p < 0.001), according to some embodiments. FIG. 33B is a plot depicting sample read coverage from Illumina sequencing as a function of parasites μL-1 wherein patients 09, 02, and 11 were analyzed to cover a wide range of parasite counts (* p < 0.05, ** p < 0.01, *** p < 0.001) and read coverage was calculated by dividing the read count by the number of probes (185) in each sample, according to some embodiments. FIG. 34 is a diagram depicting malaria pDBS card design iterations, according to some embodiments. FIG. 35A is a scanned image of card B, according to some embodiments. FIG. 35B is a rendering of card B, according to some embodiments. FIG. 35C is a rendering of a single channel of laser cut TFN, according to some embodiments. FIG. 35D is a Drabkin’s assay analysis to determine extraction zone volume and shown generally no significant difference between hematocrits, according to some embodiments. FIG. 36A is a rendering of card A, according to some embodiments. FIG. 36B is a diagram of card A comprising two layers of Leukosorb and a single layer of TFN, according to some embodiments. FIG. 36C is a plot depicting the results of a Drabkin’s assay analysis to determine extraction zone volume, according to some embodiments. FIG. 37 shows WBC depletion analyzed by qPCR for card A, card B, and 903 card, according to some embodiments. FIG. 38 depicts plots related to the matched volume of liquid reference samples, according to some embodiments. FIG. 39 depicts data related to WBC depletion and iRBC movement, according to some embodiments. FIG. 40 depicts data related to WBC depletion and iRBC movement specifically to difference in Ct value between genes and between sample types as well as iRBC enrichment in Card B compared to reference samples and a 903 card, according to some embodiments. FIG. 41 depicts instrument cycling conditions when analyzing 903 cards and LDC with a QuantStudio3 Real Time PCR system, according to some embodiments. DETAILED DESCRIPTION Malaria remains one of the greatest threats to health stability throughout the tropical regions in Africa, South America, and Asia. Moreover, malaria infections and drug resistance disproportionally affect those in limited resource settings and pose a significant challenge, exacerbating the impact on these vulnerable populations due to constrained access to effective treatments. Collection and repeat sampling of blood from malaria-infected patients may mitigate the impact of drug-resistant malaria over a population. However, malaria parasites may be developing resistance to detection with the currently used rapid diagnostic devices (RDTs). Improved diagnostics for malaria would be advantageous. When off-site, rather than point-of- care, analysis is required, a dried blood spot (DBS) card (e.g., Whatman 903 Protein Saver card) may be used for the collection and stabilization of blood components. Some DBS cards have no physical method of controlling the volume of sample applied to the paper card. Separate zones on some DBS cards are loosely defined by a dashed circle to guide manual sample application by a user, which often results in heterogeneous sample spots that vary in quality—the distribution of cells is not controllable. Once blood has dried on a DBS card, biopsy punches may be used to isolate sample discs for processing (e.g., sample elution). Contamination of samples with host DNA can be a challenging obstacle, especially in limited resource settings. The presence of host genetic material (e.g., white blood cells (WBCs)) can negatively affect the efficiency of downstream genetic analysis for malaria-infected blood samples. It may be advantageous to reduce or limit error resulting from inconsistencies in sample punching, extraction, and preparation to avoid analytical errors. Moreover, blood with a low hematocrit (i.e., high plasma volume) may spread farther than those with a higher hematocrit (i.e., low plasma volume), which can change the cellular distribution throughout the width of the DBS zone. Inconsistencies in sample processing using DBS cards may limit the kinds of samples and analyses that are possible once cards are delivered to a lab. Likewise, preservation methods such as treatment with protein denaturation reagents can limit later analysis (e.g., by preventing serological analysis). Improved drying times may also be desirable, since without wishing to be bound by any particular theory, long drying times can lead to degradation of nucleic acids and make measurements no longer quantitative or commensurate with the standard liquid blood sample. The devices provided herein may use porous materials to transport fluids by wicking. In some embodiments, this form of fluid transport helps make the devices suitable for operation in field settings where RDT or DBS cards may be used. The devices may be assembled from multiple layers of patterned paper and other porous materials and may be configured to allow segregation of blood components, including red cells, white blood cells and plasma. The devices provided herein may improve sensitivity and specificity of detection for a wide range of blood- borne pathogens, including but not limited to malaria, including Leishmania, Babesia, trypanosomes, filarial diseases, and innumerable viral blood-borne pathogens. Each layer in the device can be modified to either allow or impede the transport of specific types of cells in whole blood in a single step without the use of external equipment. In some embodiments, a drop of blood may be applied to the device to initiate a separation without further input from a user. For patients infected with malaria, a device provided herein may allow the white cells in a blood sample to quickly and efficiently be separated from the red cells while remaining available for subsequent analysis. The separation of red and white blood cells may have advantages for next- generation sequencing approaches, since without wishing to be bound by any particular theory, contamination with human genomic DNA or ribonucleic acid (RNA) may hamper the detection of less-abundant parasite genomes in blood samples. In some embodiments, the separation of red and white blood cells may enhance sensitivity to drug resistant and / or detection-resistant pathogens. In some embodiments, fluidic devices provided herein comprise one or more layers (e.g., a first layer) comprising a porous material. In some embodiments, the device comprises a first layer comprising two or more sample receptions regions (e.g., a first sample reception region and a second sample reception region) wherein the sample reception regions are in fluidic communication with each other through a channel. In some embodiments, the first sample reception region is configured to receive a fluid (e.g., a sample) comprising white blood cells and red blood cells. The porous material, configured to retain at least a portion of the white blood cells and allow the transport of at least a portion of the red blood cells, may allow for the fluid to flow through the fluidic device such that the second sample reception region is enriched with red blood cells after application of the fluid to the first sample reception region. Any of variety of properties of the flood may be determined by evaluating (e.g., via an assay) the red blood cells in the second sample reception region, as discussed elsewhere in this disclosure. Certain aspects of this disclosure relate to fluidic devices. FIG. 1A, according to some embodiments, shows a cross-section of fluidic device 100. Fluidic device 100 comprises first layer 105. In some embodiments, first layer 105 comprises a porous material which will be discussed in detail below. First layer 105 comprises first sample reception region 110 in fluidic communication with second sample reception region 120 via channel 115. That is, first sample reception region 110 is in fluidic communication with channel 115, and channel 115 is in fluidic communication second sample reception region 120 thereby placing first sample reception region 110 in fluidic communication with second sample reception region 120. Accordingly, upon application of a fluid to first sample reception region 110, the fluid may flow from first sample reception region 110 through the channel 115 into second sample reception region 120. In some embodiments, a first sample reception region and a second sample reception region are positioned apart such that a channel is positioned therebetween. For example, as shown in FIG. 1A, first sample reception region 110 is positioned apart from second sample reception region 120 such that channel 115 is positioned therebetween and in fluidic communication with the first and second sample reception region. This is further illustrated in FIG. 1B which shows a plan view of fluidic device 100, according to some embodiments. When a fluid is applied to first sample reception region 110, at least a portion of the fluid may flow generally toward second sample reception region 120 along direction 125 via channel 115. In some embodiments, as the fluid flows along direction 125, cells (e.g., white blood cells) may be immobilized while flowing through the first sample reception region and the channel prior to entry into the second sample reception region. In some embodiments, a portion of a channel is positioned between a first and second sample reception region while another portion of the channel extends beyond the second sample reception region. For example, as shown in FIG. 1C, first portion 115A of channel 115 is positioned between first sample reception region 110 and second sample reception region 120 while second portion 115B of channel 115 extends beyond second sample reception region 120. In some embodiments, the second portion of the channel extending beyond the second sample reception region may extend in a direction that is substantially parallel to the direction of flow within the fluidic device (e.g., direction 125). In some embodiments, the channel may extend beyond the second sample reception region to limit concentration of one or more types of cells (e.g., white blood cells and / or red blood cells) in an irregular manner across the second sample reception region relative to the concentration of cells across the channel and / or the first sample reception region. In some embodiments, a channel extends through at least a portion of the thickness of one or more layers of a fluidic device. In some embodiments, the channel extends through at least a portion of the thickness of the first layer. For example, as shown in FIG. 1A, channel 115 extends through the entire thickness T1 of first layer 105. When first sample reception region 110 receives the fluid, the fluid may flow from first sample reception region 110 to channel 115 throughout thickness T1 of first layer 105. It should be noted that while the geometric shape of the first and second sample reception regions, as shown in FIG. 1B, may be depicted as a circle, such depiction is for illustrative purposes, and accordingly, the first and second sample reception regions may resemble any of a variety of suitable shapes including but not limited to polygons (e.g., rectangles, squares, triangles) or ellipses. In some embodiments, a fluidic device comprises exactly one layer, such as exactly one layer having one or more of the features shown in one or more of FIGS. 1A-1C (e.g., first and second sample reception regions and a channel). As mentioned above, in some embodiments, fluidic devices described herein comprise more than one layer. For example, as shown in FIG. 2A, fluidic device 200 comprises two layers. Fluidic device 200 comprises second layer 205 disposed on first layer 105. As used herein, when a layer is referred to as being “on” or “disposed on” another layer, it can be directly disposed on the layer, or an intervening layer also may be present. A layer that is “directly on” or “directly disposed on” another layer is positioned with respect to the layer such that no intervening layer is present. Second layer 205, as shown in FIG. 2A, comprises vertical transport region 210 in fluidic communication with first sample reception region 110 and second sample reception region 120 (the latter via first sample reception region 110 and channel 115). As also shown in FIG. 2A, the vertical transport region 210 is positioned between an environment external to the fluidic device and the first sample reception region. In some embodiments, a fluid may be applied to vertical transport region 210, rather than directly to first sample reception region 110. The fluid may then flow from vertical transport region 210 to first sample reception region 110 through channel 115 to second sample reception region 120. In some embodiments, the vertical transport region may serve as a filter for cells (e.g., white blood cells) as described elsewhere in this disclosure. In some embodiments, a second layer, and / or any additional layers, may be disposed on a first layer such that only a portion of the first layer overlaps the second layer (i.e., is positioned between the first layer and an environment external to the fluidic device) and / or any additional layers. For example, as shown in FIG. 2A, only a portion of first layer 105 overlaps second layer 205. However, in some embodiments, all of the first layer may overlap the second layer and / or any additional layers. For example, as shown in FIG. 2B, all of first layer 105 overlaps second layer 205. Accordingly, a surface of the second layer and / or any additional layers may have the same or a different overall geometric size compared to the first layer. When a second layer partially or fully overlaps a first layer, it may overlap one or more sample reception regions therein (e.g., a first sample reception region, a second sample reception region) and / or a channel therein. In some embodiments, fluidic devices herein comprise three or more layers. For example, as shown in FIG. 3, fluidic device 300 comprises second layer 205 disposed on first layer 105. Third layer 305 is disposed on second layer 205. Similar to second layer 205, third layer 305 comprises second vertical transport region 310 in fluidic communication with first vertical transport region 210, first sample reception region 110, channel 115, and second sample reception region 120. Similar to the first vertical transport region, in some embodiments, the fluid may be applied to the second vertical transport region such that a portion of the fluid flows through the fluidic device (e.g., through the first vertical transportation region, first sample reception region, and the channel) to the second sample reception region. In some embodiments, layers of a fluidic device comprise the porous material. The porous material may, upon exposure to a fluid sample, wick the fluid sample into the layer and / or wick the fluid sample through the layer. When layers comprising channels comprise a porous, absorbent material, the porous, absorbent material may wick the fluid sample into the channels therein and / or through the channels therein. In some embodiments, a fluid may flow into and / or through a porous material due to capillarity (capillary action) or by wicking. In some embodiments, a fluid sample may flow into and / or through a porous material due to capillarity. In some embodiments, a porous material will, upon exposure to a fluid sample (e.g., a fluid sample of interest, a fluid sample for which it is absorbent), transport the fluid sample into the interior of the porous material (i.e., the fluid sample may penetrate into the interior of the material in which the pores are positioned, such as into the interior of fibers making up a porous material that comprises fibers). In some embodiments, a porous material will, upon exposure to a fluid sample, experience an increase in mass due to the fluid sample absorbed therein. It should be understood that some layers comprising porous absorbent materials may have one or more of the properties described above with respect to porous materials. In some embodiments, a porous material is configured to retain a portion of white blood cells. In some embodiments, when a fluid comprising white blood cells is provided to the fluidic device (e.g., via the first sample reception region), a portion of the white blood cells are retained within the porous material. Without wishing to be bound by any particular theory, the white blood cells may be filtered and / or separated from the rest of the fluid such that, as the fluid flows through the fluidic device, white bloods cells immobilize within the porous material prior to the fluid reaching the second sample reception region. That is, white blood cells may not flow through the porous material. When the fluid reaches the second sample reception region, the fluid in the second sample reception region may comprise a lower amount of white blood cells than the amount of white blood cells in the fluid when initially provided to the fluidic device. Accordingly, the first sample reception region, the channel, and / or any vertical transport regions, each comprising the porous material, may be enriched with white bloods cells while the second sample reception region may be relatively depleted of white blood cells. The separation of white blood cells from the fluid may advantageously facilitate further processing (e.g., assaying) of the second sample reception region. In some embodiments, a porous material is configured to retain a relatively large amount of white blood cells upstream from the second sample reception region upon application of a sample comprising red and white blood cells thereto. Similarly, some methods comprise retaining a relatively large amount of white blood cells upstream from the second sample reception region upon application of a sample comprising red and white blood cells thereto. In some embodiments, the porous material is configured to retain greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, greater than or equal to 95%, greater than or equal to 99%, or greater than or equal to 99.9% of white blood cells upstream from the second sample reception region. In some embodiments, the porous material is configured to retain less than or equal to 99.9%, less than or equal to 99%, less than or equal to 95%, less than or equal to 90%, less than or equal to 85%, less than or equal to 80%, or less than or equal to 75% of white blood cells upstream from the second sample reception region. Combinations of these ranges are possible (e.g., greater than or equal to 75% and less than or equal to 99.9%). Other ranges are also possible. Some methods may comprise retaining an amount of white blood cells upstream from the second sample reception region in one or more of the above-referenced ranges. In some embodiments, a porous material is configured to allow transport of red blood cells to a second sample reception region via a channel. That is, the porous material may allow for red blood cells in the fluid to flow through the fluidic device, without being immobilized, such that at least a portion of the red blood cells in the fluid are capable of moving through the porous material to enter the second sample reception region. In view of the above and the present disclosure as a whole, the porous material may promote the immobilization of white blood cells while allowing for the flow and / or transport (e.g., movement) of red blood cells. In such embodiments, the porous material may be configured to transport red blood cells therethrough to a higher degree than white blood cells. The separation of white blood cells and red blood cells in a fluidic device may facilitate relatively greater efficiency for further processing (e.g., genetic sequencing) as host contamination of the sample (e.g., a punch of the second sample reception region) may be generally limited. Moreover, the porous material, in some embodiments, may allow for the transport of, in addition to red blood cells, pathogens (and / or nucleic acids and / or other genetic materials derived from pathogens) that may be present in the fluid to the second sample reception region. In some embodiments, a porous material is configured to allow red blood cells in a fluid to flow (e.g., move) through the device away from the first sample reception region. In some embodiments, the porous material is configured to allow transport of greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, greater than or equal to 95%, greater than or equal to 99%, or greater than or equal to 99.9% of red blood cells in the fluid to flow through the device away from the first sample reception region. In some embodiments, the porous material is configured to allow transport of less than or equal to 99.9%, less than or equal to 99%, less than or equal to 95%, less than or equal to 90%, less than or equal to 85%, less than or equal to 80% of red blood cells in the fluid to flow through the device away from the first sample reception region. Combinations of these ranges are possible (e.g., greater than or equal to 80% and less than or equal to 99.9%). Other ranges are also possible. In some embodiments, a porous material has a relatively high porosity. In some embodiments, the median pore size of the porous material is greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 15 micrometers, greater than or equal to 20 micrometers, greater than or equal to 25 micrometers, greater than or equal to 30 micrometers, greater than or equal to 35 micrometers, or greater than or equal to 40 micrometers. In some embodiments, the median pore size of the porous material is less than or equal to 40 micrometers, less than or equal to 35 micrometers, less than or equal to 30 micrometers, less than or equal to 25 micrometers, less than or equal to 20 micrometers, less than or equal to 15 micrometers, less than or equal to 10 micrometers, less than or equal to 5 micrometers. Combinations of these ranges are possible (e.g., greater than or equal to 5 micrometers and less than or equal to 40 micrometers). Other ranges are also possible. In some embodiments, a porous material has any of a variety of suitable thicknesses. In some embodiments, the porous material has a relatively large thickness. In some embodiments, the porous material has a thickness of greater than or equal to 300 micrometers, greater than or equal to 400 micrometers, greater than or equal to 500 micrometers, greater than or equal to 600 micrometers, or greater than or equal to 700 micrometers. In some embodiments, the porous material has a thickness of less than or equal to 700 micrometers, less than or equal to 600 micrometers, less than or equal to 500 micrometers, less than or equal to 400 micrometers, or less than or equal to 300 micrometers. Combinations of these ranges are possible (e.g., greater than or equal to 300 micrometers and less than or equal to 700 micrometers). Other ranges are also possible. In some embodiments, a porous material comprises any of a variety of suitable compositions. In some embodiments, the porous material comprises a material configured to retain a portion of white blood cells (e.g., while allowing red blood cells to flow and / or move therethrough). For instance, the porous material comprises a polyester having this property. In some embodiments, the porous material comprises a partially hydrolyzed polyester. In some embodiments, the porous material comprises a white blood cell isolation medium and / or a white blood cell filter such as Leukosorb. In some embodiments, the porous material comprises cellulose acetate and / or a cellular acetate filter. A wide variety of porous materials may be used for this purpose such as those manufactured by Pall Corporation, those manufactured by Sartorius, and / or those manufactured by Cytiva. In some embodiments, the porous material comprises a plurality of fibers that may allow for advantageous connectivity of pores within the porous material. In some embodiments, the porous material may be functionalized and / or subjected to any of a variety of chemical treatments that may alter the surface properties of the porous material. In some embodiments, the porous material, when exposed to the fluid, functions in a manner similar to a size exclusion filter. That is, a portion of the fluid (e.g., white blood cells) having a size greater than a threshold may be retained by the porous material while a portion of the fluid have a size less than the threshold (e.g., red blood cells) may flow through the porous material. In some embodiments, the porous material is a membrane and / or a polymer mesh. In some embodiments, a porous material comprises a material that allows white blood cells to flow therethrough. For instance, the porous material may comprise a synthetic material and / or a glass. Non-limiting examples of suitable synthetic materials include poly(ether sulfone), polyesters, and nylons. In some embodiments, a porous material that allows white blood cells to flow therethrough is a cellulose-based material. The cellulose-based material may comprise cellulose derived from wood (e.g., it may be a wood-based material), cellulose derived from cotton (e.g., it may be a cotton-based material), and / or nitrocellulose. Porous materials described herein may have a variety of designs. In some embodiments, a fluidic device comprises a porous material that is a fibrous material (e.g., a fibrous material comprising fibers formed from a cellulose-based material). The fibrous material may be a non- woven material, or may be a woven material. The fibers may have a variety of suitable diameters and distributions of diameters, and, if woven, may be woven in a variety of suitable weaves. In some embodiments, the non-woven material is a paper. For instance, in designs that are configured to allow white blood cells to flow through the porous material, cellulose-based papers may be used. A wide variety of commercially available cellulose-based papers may be employed, such as those manufactured by Whatman, those manufactured by Ahlstrom, and / or those manufactured by Munktell. In some embodiments, a porous material may allow for relatively quick drying times. In some embodiments, when a 50 microliter sample of the fluid is provided to the first sample reception region, the sample is capable of drying less than or equal to 60 minutes, less than or equal to 55 minutes, less than or equal to 50 minutes, less than or equal to 45 minutes, less than or equal to 40 minutes, less than or equal to 35 minutes, or less than or equal to 30 minutes while in an environment having a relative humidity of 40%. In some embodiments, the above- described ranges may characterize the porous material upon application of a sample having a hematocrit of greater than or equal to 25% and less than or equal to 55% thereto. In some embodiments, when a 50 microliter sample of the fluid is provided to the first sample reception region, the sample is capable of drying greater than or equal to 30 minutes, greater than or equal to 35 minutes, greater than or equal to 40 minutes, greater than or equal to 45 minutes, greater than or equal to 50 minutes, greater than or equal to 55 minutes, or greater than or equal to 60 minutes while in an environment having a relative humidity of 40%. In some embodiments, the above-described ranges may characterize the porous material upon application of a sample having a hematocrit of greater than or equal to 25% and less than or equal to 55% thereto. Combinations of these ranges are possible (e.g., greater than or equal to 30 minutes and less than or equal to 60 minutes). Other ranges are also possible. In some embodiments, the aforementioned drying times may be achieved in an environment having any of a variety of suitable relative humidities. In some embodiments, the environment may have a relative humidity greater than or equal to 20%, greater than or equal to 25%, greater than or equal to 30%, greater than or equal to 35%, and greater than or equal to 40%. In some embodiments, the environment may have a relative humidity less than or equal to 40%, less than or equal to 35%, less than or equal to 30%, less than or equal to 25%, or less than or equal to 20%. Combinations of these ranges are possible (e.g., greater than or equal to 20% and less than or equal to 40%). Other ranges are also possible. In some embodiments, a porous material may retain one or more types of cells electrostatically. In some embodiments, the porous material may separate portions of the fluid based on electrostatic charge differentials between portions of the fluid (e.g., red and / or white blood cells, pathogens) and the porous material. In some embodiments, the porous material may retain white blood cells via electrostatic attraction between the porous material and the white blood cells. In some embodiments, the porous material may allow for red blood cells to flow as there may be little to no electrostatic attraction between the red blood cells and the porous material. In some embodiments, the retention and / or flow of cells through the fluidic device may, at least in part, be electrostatically mediated. In some embodiments, a porous material described herein may have any of a variety of suitable porosities. In some embodiments, the porous material has an advantageously high porosity. In some embodiments, the porous material has a porosity greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, greater than or equal to 80%, greater than or equal to 90%. In some embodiments, the porous material has a porosity less than or equal to 90%, less than or equal to 80%, less than or equal to 70%, less than or equal to 60%, or less than or equal to 50%. Combinations of these ranges are possible (e.g., greater than or equal to 50% and less than or equal to 90%). Other ranges are also possible. In some embodiments, a fluidic device comprises a porous material that is hydrophilic and / or may comprise a layer that is hydrophilic (e.g., a layer comprising a hydrophilic porous material). The hydrophilic material or layer may have a water contact angle of less than or equal to 90°, less than or equal to 85°, less than or equal to 80°, less than or equal to 75°, less than or equal to 70°, less than or equal to 65°, less than or equal to 60°, less than or equal to 55°, less than or equal to 50°, less than or equal to 45°, less than or equal to 40°, less than or equal to 35°, less than or equal to 30°, less than or equal to 25°, less than or equal to 20°, less than or equal to 15°, less than or equal to 10°, or less than or equal to 5°. The hydrophilic material or layer may have a water contact angle of greater than or equal to 0°, greater than or equal to 5°, greater than or equal to 10°, greater than or equal to 15°, greater than or equal to 20°, greater than or equal to 25°, greater than or equal to 30°, greater than or equal to 35°, greater than or equal to 40°, greater than or equal to 45°, greater than or equal to 50°, greater than or equal to 55°, greater than or equal to 60°, greater than or equal to 65°, greater than or equal to 70°, greater than or equal to 75°, greater than or equal to 80°, or greater than or equal to 85°. Combinations of the above-referenced ranges are also possible (e.g., less than or equal to 90° and greater than or equal to 0°). Other ranges are also possible. The water contact angle of a hydrophilic material or layer may be measured using ASTM D5946-04, which comprises positioning a water droplet on a planar solid surface of the hydrophilic material or layer. The water contact angle is the angle between the planar solid surface of the hydrophilic material or layer and the tangent line drawn to the water droplet surface at the three-phase point. A contact angle meter or goniometer can be used for this determination. In some embodiments, the hydrophilicity of the hydrophilic material or layer may be such that a water droplet placed on the surface completely wets the surface (e.g., the water droplet is completely absorbed into the material, making the water contact angle 0°). In some embodiments, a device may comprise a porous material that is hydrophobic and / or may comprise a layer that is hydrophobic. The hydrophobic material or layer may have a water contact angle outside the ranges described above. In some embodiments, a porous material described herein is a porous, absorbent material. In some embodiments, the porous, absorbent material may be absorbent and also have any of the properties of the porous material described herein. In some embodiments, the porous, absorbent, material, upon exposure to a fluid sample, wick the fluid sample into the material itself (e.g., in addition to wicking the fluid into any pores therein). For instance, if a porous, absorbent material is fibrous, it may wick a fluid sample into the fibers therein. In some embodiments, a porous material described herein is non-absorbent. Such porous, non-absorbent materials, in some embodiments, do not, upon exposure to a fluid sample, wick the fluid sample into the material itself. Porous, non-absorbent materials may, however, wick the fluid sample into pores therein and / or therethrough (e.g., via pores therein). Moreover, when layers comprising channels comprise the porous material, the porous material may wick the fluid sample into the channels therein and / or through the channels therein without wicking the fluid sample into the porous material itself. For instance, if a porous, non-absorbent material is fibrous, it may wick a fluid sample through the material without wicking into the fibers therein. In some embodiments, fluidic devices described herein comprise a first sample reception region. In some embodiments, the first sample reception region is configured to receive the fluid either directly or via one or more vertical transport regions. In some embodiments, the first sample reception region comprises the porous material, and accordingly, the first sample reception region may transport a portion of the fluid through the fluidic device while immobilizing white blood cells. In some embodiments, the first sample reception region may be enriched with white bloods cells. That is, the first sample reception region may have a higher concentration of white bloods cells than in one or more other portions of the fluidic device, such as the second sample reception region. In some embodiments, the first sample reception may comprise a material other than the porous material forming the channel. For instance, the first sample reception region, in accordance with certain embodiments, may comprise cellulosic paper and the porous material may be a material other than cellulosic paper or may be a different type of cellulosic paper. In some embodiments, fluidic devices described herein comprise a second sample reception region. In some embodiments (e.g., after the application of a fluid thereto), the second sample reception region is enriched with one or more components of the fluid. For instance, red blood cells and / or, when the fluid initially comprises pathogens, pathogens (e.g., bloodborne pathogens). As the fluid flows through the fluidic device, white blood cells may be immobilized by the porous material of the fluidic device, as described above, thereby enriching the fluid that enters the second sample reception region with red blood cells and / or pathogens. In some embodiments, a portion of the red blood cells and / or pathogens may be retained in or on the second sample region. When biological material (e.g., red blood cells, white blood cells, and / or pathogens) are retained in or on a region of the fluidic device, the biological material may be positioned in an interior of the region such that the biological material is within the geometric confines of the corresponding layer of the fluidic device where the region resides and / or the geometric confines of the region itself. In some embodiments, the biological material retained in or on the region may be disposed on the region, positioned within pores of the region, and / or wicked into the interior of any absorptive component (e.g., the porous material) of the region such that the biological material is immobilized in the interior of the region. It should be noted that immobilization of biological material generally refers to the relative restriction of movement and / or transport of biological material, but some, albeit limited, movement and / or transport of immobilized biological material may still be possible. The second sample region may, in some such embodiments, be enriched with red blood cells and / or pathogens (if initially present in the fluid) retained in or on the second sample region (e.g., in comparison to another region of the fluidic device). In some embodiments, the red blood cells and / or pathogens may be retained on the second sample reception region after drying of the second sample region. In some embodiments, the second sample reception region provides a region of the fluidic device that may be punched such that the second sample reception region may be removed from the fluidic device for further analysis. Accordingly, the second sample reception region may be considered a punch region where a portion of the fluidic device is removed from further processing (e.g., assaying). In some embodiments, fluidic devices described herein having a second sample reception region enriched with red blood cells and / or pathogens may be advantageous. In some embodiments, the enrichment of the second sample reception region with red blood cells and / or pathogens may facilitate assaying of the second sample reception region with assays involving red blood cells and / or pathogens (e.g., Drabkin’s assay) with limited contamination from white blood cells. Likewise, in some embodiments, the enrichment of the first sample reception region with white blood cells may facilitate assaying of the first sample reception region with assay involving white blood cells with limited contamination from red blood cells and / or pathogens. It is also possible for a fluidic device to comprise a first sample reception region that is enriched with pathogens. For instance, in some embodiments, a sample applied to a fluidic device described herein may comprise a pathogen that is retained by a porous material present in a first sample reception region and / or a channel. In such embodiments, the fluidic device may serve to separate the pathogen from red blood cells. Additionally, in such embodiments, the first sample reception region may be enriched in the pathogen. In some embodiments, a second sample reception region is positioned along a channel at any variety of suitable distances away from the first sample region. For example, as shown in FIG. 1A, first sample reception region 110 is positioned at distance D1 away from second sample reception region 120. In some embodiments, the second sample reception region is positioned along the channel greater than or equal to 10 mm, greater than or equal to 15 mm, greater than or equal to 20 mm, greater than or equal to 25 mm, or greater than or equal to 30 mm from the first sample reception region. In some embodiments, the second sample reception region is positioned along the channel less than or equal to 30 mm, less than or equal to 25 mm, less than or equal to 20 mm, less than or equal to 15 mm, or less than or equal to 10 mm from the first sample reception region. Combinations of these ranges are possible (e.g., greater than or equal to 10 mm and less than or equal to 30 mm). Other ranges are also possible. In some embodiments, a first and / or second sample reception region is configured to contain any of a variety of suitable volumes. In some embodiments, the first and / or second sample reception region is configured to contain a volume of greater than or equal to 40 microliters, greater than or equal to 45 microliters, greater than or equal to 50 microliters, greater than or equal to 55 microliters, greater than or equal to 60 microliters, greater than or equal to 65 microliters, or greater than or equal to 70 microliters of a fluid sample (e.g., a liquid sample). In some embodiments, the first and / or second sample reception region is configured to contain a volume of less than or equal to 70 microliters, less than or equal to 65 microliters, less than or equal to 60 microliters, less than or equal to 55 microliters, less than or equal to 50 microliters, less than or equal to 45 microliters, or less than or equal to 40 microliters of a fluid sample (e.g., a liquid sample). Combinations of these ranges are possible (e.g., greater than or equal to 40 microliters and less than or equal to 70 microliters). Other ranges are also possible. In some embodiments, a second sample reception region is positioned along a channel such that a portion of cells (e.g., red and / or white blood cells) in the fluid is distributed on the second sample reception region such that a concentration of cells in the second sample region is relatively similar to the concentration of the cells at another position along the channel outside the second sample region. In some embodiments, the concentration of red blood cells in the second sample region is greater than or equal to 80%, greater than or equal to 90%, greater than or equal to 100%, greater than or equal to 110%, or greater than or equal to 120% of the concentration of the red blood cells at another position along the channel outside the second sample reception region. In some embodiments, the concentration of red blood cells in the second sample region is less than or equal to 120%, less than or equal to 110%, less than or equal to 100%, less than or equal to 90%, or less than or equal to 80% of the concentration of the red blood cells at another position along the channel outside the second sample reception region. Combinations of these ranges are possible (e.g., greater than or equal to 80% and less than or equal to 120%). Other ranges are also possible. In some embodiments, fluidic devices described herein comprise a channel. In some embodiments, the channel places the first sample reception region in fluidic communication with the second sample reception region such that a portion of the fluid, when provided to the fluidic device, may flow through the fluidic device to the second sample reception region. In some embodiments, the channel comprises the porous material thereby immobilizing at least some of the white blood cells in the fluid. Accordingly, in some embodiments, some or all of the channel may be enriched with white blood cells. In some embodiments, a channel of fluidic devices described herein may have any of a variety of suitable lengths. For example, as shown in FIG. 1C, channel 115 has length L1 extending from first sample reception region 110 to the end of channel 115. In some embodiments, where the channel does not extend beyond the second sample reception region, the length of the channel may correspond to the length between the first and second sample reception regions. For example, as shown in FIG. 1B, channel 115 has length L2 extending from first sample reception region 110 to second sample reception 120. In some embodiments, the channel has a length greater than or equal to 10 mm, greater than or equal to 15 mm, greater than or equal to 20 mm, greater than or equal to 25 mm, greater than or equal to 30 mm, greater than or equal to 35 mm, or greater than or equal to 42 mm. In some embodiments, the channel has a length less than or equal to 42 mm, less than or equal to 35 mm, less than or equal to 30 mm, less than or equal to 25 mm, less than or equal to 20 mm, less than or equal to 15 mm, or less than or equal to 10 mm. Combinations of these ranges are also possible (e.g., greater than or equal to 10 mm and less than or equal to 42 mm). Other ranges are also possible. It should be noted that while a channel is positioned between a first sample reception region and a second sample region, some embodiments of the fluidic devices described herein do not comprise the channel. That is, the first and second sample reception regions may not be positioned apart with a channel therebetween. In such embodiments, the length of the channel may correspond to the summation of the lengths of the first and second sample reception regions. In some embodiments, a channel of fluidic devices described herein may have any of a variety of suitable thicknesses. In some embodiments, the channel may have a thickness greater than or equal to 400 micrometers, greater than or equal to 500 micrometers, greater than or equal to 600 micrometers, greater than or equal to 700 micrometers, or greater than or equal to 800 micrometers. In some embodiments, the channel may have a thickness less than or equal to 800 micrometers, less than or equal to 700 micrometers, less than or equal to 600 micrometers, less than or equal to 500 micrometers, or less than or equal to 400 micrometers. Combinations of these ranges are possible (e.g., greater than or equal to 400 micrometers and less than or equal to 800 micrometers). Other ranges are also possible. In some embodiments, a channel of fluidic devices described herein may have any of a variety of suitable porosities. In some embodiments, the channel has a porosity greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, greater than or equal to 80%, greater than or equal to 90%. In some embodiments, the channel has a porosity less than or equal to 90%, less than or equal to 80%, less than or equal to 70%, less than or equal to 60%, or less than or equal to 50%. Combinations of these ranges are possible (e.g., greater than or equal to 50% and less than or equal to 90%). Other ranges are also possible. In some embodiments, a channel of fluidic devices described herein may have any of a variety of suitable widths. For example, as shown in FIG. 1B, channel 115 has width W1. In some embodiments, the width of the channel may influence flow (e.g., flow may be arrested if the width of the channel is unsuitably narrow or flow may be slow if the width of the channel is unsuitably large). In some embodiments, the channel has a width greater than or equal to 2 mm, greater than or equal to 3 mm, greater than or equal to 4 mm, greater than or equal to 5 mm, greater than or equal to 6 mm, greater than or equal to 7 mm, or greater than or equal to 8 mm. In some embodiments, the channel has a width less than or equal to 8 mm, less than or equal to 7 mm, less than or equal to 6 mm, less than or equal to 5 mm, less than or equal to 4 mm, less than or equal to 3 mm, or less than or equal to 2 mm. Combinations of these ranges are also possible (e.g., greater than or equal to 2 mm and less than or equal to 8 mm). Other ranges are also possible. In some embodiments, when exposed to a volume of a fluid comprising whole blood that is greater than or equal to a volume of a channel, the fluid fills both first and second sample reception regions. In some embodiments, when exposed to a volume of whole blood that is greater than or equal to a volume of the channel and that has a hematocrit value of greater than or equal to 25% and less than or equal to 55%, the whole blood fills both the first and second sample reception regions. In some embodiments, when exposed to a volume of whole blood that has a hematocrit value of greater than or equal to 25% and less than or equal to 55%, the amount of the second sample reception region filled by the whole blood is substantially independent of the hematocrit value. That is, when the hematocrit value of the fluid is greater than or equal to 25% and less than or equal to 55%, the fluidic device is configured such that, upon application of the fluid, the fluid fills the sample reception region to the same extent regardless of where the hematocrit value is within the aforementioned range. In some embodiments, fluids may be provided to fluidic devices described herein. In some embodiments, the fluid comprises a biological fluid (e.g., blood). In some embodiments, the fluid comprises whole blood. In some embodiments, the fluid comprises white blood cells and red blood cells. In some embodiments, the fluid comprises pathogens. In some embodiments, the fluid comprises white blood cells and pathogens. In some embodiments, the fluid comprises white blood cells, red blood cells, and pathogens. In some embodiments, the fluid comprises a bloodborne pathogen and / or biological material-derived from a bloodborne pathogens. The fluidic device may advantageously facilitate the detection of bloodborne pathogens in a blood sample by separating white blood cells, which may interrupt and / or interfere with the detection of the bloodborne pathogens, from the rest of the fluid. In some embodiments, the fluid further comprises nucleic acids from one or more pathogens (e.g., parasites, bacteria, viruses). In some embodiments, the bodily fluid comprises bloods, tears, saliva, wound exudate, urine, cerebrospinal fluid, and / or sweat. In some embodiments, the liquid comprises a fluid derived from the bodily fluid (e.g., plasma derived from blood). In some embodiments, the liquid comprises an aqueous solution. In some embodiments, fluids may be provided to fluidic devices described herein. In some embodiments, the fluid may be provided to the first sample reception region and / or to any vertical transport regions of the fluidic device. In some embodiments, a volume of fluid may be provided to the fluidic device sufficient for the fluid to through the channel to the second sample reception region such that the concentration of cells (e.g., red blood cells) is not significantly different than the concentration of cells at a location in the channel proximate to the second sample reception region. In some embodiments, fluidic devices described herein comprise a second layer. In some embodiments, the second layer comprises a porous material. In some embodiments, the second layer comprises the same material (e.g., the porous absorbent material) as the first layer. In some embodiments, the second layer comprises a porous material that is different than the first layer. In some embodiments, the second layer may guide and / or direct flow of the fluid through the fluidic device as the second layer may comprise wax portions that may not wet in the presence of the fluid. The wax portions may then direct the fluid to wet other portions of the first and / or second layer comprising a porous material. In some embodiments, the second layer comprises a vertical transport region in fluidic communication with the first sample reception region and the second sample reception region. A fluid may be provided to the vertical transport region of the fluidic device such the vertical transport region transports a portion of the fluid vertically toward another layer of the fluidic device. In some embodiments, the vertical transport region is a white blood cell filter in fluidic communication with the first sample reception region, the second sample reception region, and / or the channel. The vertical transport region may then facilitate the separation and / or the immobilization of white blood cells when provided the fluid, thereby allow red blood cells to flow throughout the fluidic device. In some embodiments, the vertical fluid transport region is positioned external to the fluidic device and the channel such that the vertical fluid transport region may separate and / or immobilize at least some white blood cells prior to entry of the fluid into the fluidic device and / or the channel. In embodiments in which both a vertical transport region in a second layer of a fluidic device described herein and a porous material present in one or more portions of a first layer of a fluidic device described herein (e.g., a first sample reception region, a second sample reception region, a channel) are both white blood cell filters, they may be different white blood cell filters or may be the same type of white blood cell filter. In some embodiments, fluidic devices described herein comprise a nucleic acid stabilizer. When present, the nucleic acid stabilizer may be present in any suitable portion of the fluidic device, such as in a layer thereof, a first sample reception region, a second sample reception region, a channel (e.g., a channel fluidically connecting two sample reception regions), and / or a vertical transport region. The nucleic acid stabilizer may advantageously stabilize nucleic acids (e.g., DNA, RNA) such that nucleic acids may be recovered after a relatively long duration of time after the fluid has dried on and / or within the fluidic device. In some embodiments, the nucleic acid stabilizer allows for nucleic acids to be recovered after a period of greater than or equal to 1 month, greater than or equal to 3 months, greater than or equal to 6 months, or greater than or equal to 12 months of drying the device. In some embodiments, the nucleic acid stabilizer allows for nucleic acids to be recovered after a period of less than or equal to 12 months, less than or equal to 6 months, less than or equal to 3 months, or less than or equal to 1 month. Combinations of these ranges are possible (e.g., greater than or equal to 1 month and less than or equal to 12 months). Other ranges are also possible. In some embodiments, a method comprises recovering a nucleic acid (e.g., DNA, RNA) from a fluidic device and / or a component thereof (e.g., a sample reception region, a channel, a vertical transport region, a layer). This recovery may be performed in one or more of the time periods provided in the preceding paragraph. In some embodiments, the nucleic acid stabilizer comprises an RNA stabilizer. Exemplary RNA stabilizers include but are not limited to FTA reagent and RNAlater. In some embodiments, the nucleic acid stabilizer comprises a DNA stabilizer. In some embodiments, the nucleic acid stabilizer comprises DNA Shield, RNA Shield, RNA Later, DNase and RNase inhibitors, denaturants such as guanidinium salts or surfactants (SDS), quaternary ammonium salts (such as the active ingredient in Cavicide), Qiagen RNAprotect, and / or silk. Other nucleic acid stabilizers may also be used. In some embodiments, fluidic devices described herein may facilitate the determination of a property of a fluid. In some embodiments, the fluidic device determines and / or facilitates the determination of a property of a fluid comprising a blood sample. In some embodiments, determining a property of the fluid may involve transporting (e.g., laterally transporting) the fluid through the fluidic device such that cells (e.g., a plurality of cells) are transported through the channel of the fluidic device to the second sample reception region. In some embodiments, the transporting the fluid involves transporting cells through the channel from the first sample reception region to the second sample reception region (e.g., via a channel fluidically connecting the first and second sample reception regions). In some embodiments, the transporting comprises transporting a plurality of white blood cells and a plurality of red blood cells through a fluidic device to a first region and a second region, wherein the second region is a sample reception region. In some embodiments, a first portion of the fluid (e.g., a portion comprising a portion of the plurality of white blood cells) is retained in or on the first region. In some embodiments, a second portion of the fluid (e.g., a portion comprising a portion of the plurality of red blood cells) is retained in or on the second region (e.g., the second sample reception region). In some embodiments, the first portion of the fluid may be enriched in white blood cells (e.g., in comparison to the amount of white blood cells present in the second sample reception region, as a fraction of the fluid in comparison to the fraction of the fluid occupied by white blood cells in the second sample reception region) while the second portion of the fluid may be enriched in red blood cells (e.g., in comparison to the amount of red blood cells present in the first sample reception region, as a fraction of the fluid in comparison to the fraction of the fluid occupied by red blood cells in the first sample reception region). In some embodiments (e.g., embodiments in which a bloodborne pathogen is originally present in the fluid), the second portion of the fluid is enriched in a bloodborne pathogen (e.g., in comparison to the amount of the pathogen present in the first sample reception region, as a fraction of the fluid in comparison to the fraction of the fluid occupied by the pathogen in the first sample reception region). As noted above, it is also possible for the first portion of the fluid to be enriched in a bloodborne pathogen (e.g., in comparison to the amount of the pathogen present in the second sample reception region, as a fraction of the fluid in comparison to the fraction of the fluid occupied by the pathogen in the second sample reception region). In some embodiments, fluidic devices described herein may determine and / or facilitate the determination of the presence of a bloodborne pathogen. Similarly, some methods may comprise determining the presence of a bloodborne pathogen (e.g., using a fluidic device described herein and / or on a sample present in a device described herein). In some embodiments, the bloodborne pathogen comprises parasites such as malaria, bacteria, and / or viral agents. In some embodiments, the property of a fluid involves biological material derived from a bloodborne pathogen such as malarial nucleic acids such as malarial RNA. In some embodiments, the fluidic device provides one or more samples of blood and / or samples of blood components, via a punch of the first sample reception region and / or the second sample reception region, such that the punch may be evaluated. Any of variety of suitable assays may be employed, such as RNA assays and / or Drabkin’s assay. In some embodiments, assays and / or methods that may be used to evaluated the second sample region and / or another portion of the fluidic device comprise molecular amplification assays (DNA or RNA) such as those for blood borne pathogens, selective or whole genome sequencing, serological tests, metabolite profiling, and / or hematological indices. In some embodiments, an assay may be performed that is suitable for detecting the presence and / or remnants of a bloodborne pathogens. It should be noted that, while the above description describes bloodborne pathogens, the present disclosure is not so limiting and other pathogenic materials may be involved in fluids other than blood (e.g., biological fluids such as saliva). In some embodiments, after a fluid is provided and transported through fluidic devices described herein, the fluidic device may be dried for a period of time. In some embodiments, the fluidic device may be dried in the first and / or second sample reception region such that either or both reception regions may punched and evaluated for various properties of the fluid (e.g., the presence of bloodborne pathogens). In some embodiments, after the fluidic device is dried, nucleic acids may be recovered from either sample reception region, and in some embodiments, such recovery may occur at least a month after the initial lateral transport of the fluid. The following examples are intended to illustrate certain embodiments of the present invention, but do not exemplify the full scope of the invention. EXAMPLE 1 Introduction Systems, articles, and methods related to fluidic devices are generally described in this example. A DBS card—the Leukocyte Depletion Card (LDC)—capable of depleting host DNA (by removal of WBCs) while maintaining stability of Plasmodium DNA was developed. The card was challenged with both in vitro contrived samples as well as 16 clinical samples of various WBC counts and parasite counts. The WBC depletion and subsequent parasite enrichment for LDC compared to 903 card as well as improved Plasmodium sequencing was demonstrated. An advantage of at least some devices provided in this example is that they may help provide sample cleanup or enrichment of Plasmodium DNA. Such devices may leave samples with high ratios of host DNA (e.g., which may relate to the number of white blood cells in the device) compared to parasite DNA, affecting downstream sequencing. In some embodiments, devices provided in this example are capable of depleting host white blood cells (WBCs) from whole blood and / or (optionally simultaneously) storing the sample in a dried format such that the Plasmodium DNA is preserved for downstream analysis. The hematocrit-independence of at least some devices provided in this example across 25–55% hematocrit may allow for a reproducible punch volume across different patients. Parasite enrichment may be detected, in some embodiments, in blood samples, with 0.001% or more parasitemia (e.g., up to 5%, up to 10%, up to 20%, or more parasitemia) using a device provided in this example as quantified by qPCR, according to some embodiments. The devices provided in this example, according to some embodiments, produce substantial enrichment of parasitic DNA relative to venous blood, depending on the embodiment. For example, in some embodiments, the average enrichment of parasitic DNA is greater than or equal to 100-fold, greater than or equal to 150-fold, greater than or equal to 200-fold in a device described herein relative to venous blood. In some embodiments, the average enrichment of parasitic DNA in a device described in this example relative to venous blood is as high as 250-fold. Similar enrichments in parasitic DNA may be observed, e.g., relative to a conventional DBC card such as the Whatman 903 card or a generic equivalent thereof. Quantitative cellular analysis of patient-collected, dried specimens may be improved, according to some embodiments, by: (i) control of cell distribution within the collection media, (ii) precision metering of collected volumes, and / or (iii) autonomous sample processing. The devices provided in this example may allow control of cell distribution within the device and / or the precision metering of collected volumes, in some embodiments. According to some embodiments, the devices provided in this example may be configured for precision metering of collected volumes. In some embodiments, a device provided in this example may be suitable for characterizing the nucleic acids of intraerythrocytic parasites, e.g., at least in part as a result of one of the above-mentioned advantages. A device described in this example may be useful for the preservation of RNA in the field (e.g., without use of RNA preservation solutions). Improved and field-friendly technologies would assist efforts in host nation health security, protection and treatment of deployed troops, and global efforts to study, treat, and eradicate malaria. A device provided in this example may allow both transport of RBCs (red blood cells) and also removal of WBCs. In some embodiments, transport of RBCs and removal of WBCs can help to remove host nucleic acid contaminants. A device may exhibit reduced loss of parasitized RBCs relative to a traditional DBC, thereby improving sensitivity. In some embodiments, a device increases the depletion of host WBCs, providing greater measurement specificity than a traditional DBC (see FIG. 7). A device may comprise a single or double layer of a white blood cell isolation medium (e.g., Leukosorb) before filling a patterned channel of DBS cardstock (FIG. 4 and FIG. 6A-6B). A sample of whole blood having an appropriate volume (e.g., 40 microliters) may be added to the device. (A Whatman 903 card may be used for comparison, as shown in FIG. 4.) Donor WBCs may be quantified using the 18S rRNA gene. P. falciparum may be quantified using sbp1, a conserved single copy gene. A ∆Ct may be calculated for each gene against an equal volume of whole blood. The ∆Ct may allow measurements of parasite loss, enrichment, and purity. In one example, a sample of whole blood (40% hematocrit, 1% ring stage P. falciparum, strain NF54) having a volume of 40 microliters was tested and parasite DNA was 16% that of human DNA (average Ct = 23.8 vs. 21.2). In the device comprising a single Leukosorb layer device, P. falciparum DNA purity increased to 23% while offering a 7-fold enrichment over Whatman 903. P. falciparum DNA purity increased to 84% in the double Leukosorb layer device while offering a 50-fold enrichment over Whatman 903. The improved purity observed may facilitate efforts to identify drug resistant strains by next generation sequencing. The sensitivity and specificity of quantitative RNA assays can be heavily influenced by the sample matrix, sampling environment, and storage and / or transport conditions. A device provided in this example may improve RNA stabilization. In some embodiments, a device comprises one or more zones (e.g., portions of a layer of a device) comprising an RNA stabilizer. Exemplary RNA stabilizers include but are not limited to FTA reagent and RNAlater. In some embodiments, a device comprises one or more zones comprising silk fibroin. Silk fibroin can, in some embodiments, improve RNA stabilization. Moreover, the devices provided in this example may provide improved RNA stabilization in some cases by providing rapid drying. For example, a device provided in this example may be dry within 60 minutes of use, in some embodiments. In some embodiments, a device provided in this example may stabilize RNA (e.g., from intraerthyrocytic parasites) such that it can be recovered after at least one month of storage without any spurious amplification. For example, in one example qPCR was used to successfully amplify P. falciparum RNA isolated from punches of pDBS cards without evidence of spurious amplification from contaminating human nucleic acids (FIG. 5). According to some embodiments, a fluidic device comprises two layers of porous materials. The use of two layers of porous materials is advantageous, in some embodiments, for the separation of white blood cells from red blood cells in a fluid (e.g., whole blood). In some embodiments, a device further comprises a third layer. The use of a third layer may enhance white blood cell separation relative to the white blood cell separation that could be achieved in a device with only two layers. Layers of a device are, in some embodiments, adhered together (e.g., using double-sided adhesive). One or more layers of the device may be filters. In some embodiments, filters may be used to deplete the whole blood sample of white blood cells while permitting other fluid (e.g., comprising red blood cells) to be transported to a bottom layer (e.g., a layer comprising a porous material) of the fluidic device. The filter(s) may reduce the concentration of white blood cells in the fluid transported to the bottom layer by any of a variety of appropriate amounts (e.g., at least 500-fold, relative to the concentration of white blood cells in fluid initially provided to the fluidic device. The separation of the white blood cells may be achieved using any of a variety of appropriate mechanisms, such as size exclusion and / or electrostatic attraction. The bottom layer of the device may receive fluid flow from the top layer(s) in a first sample reception region to and may channel the fluid from the first sample reception region to a second sample reception region. Fluid in the second sample collection region can be excised and analyzed during downstream analysis, according to some embodiments. The device may be operated by applying a fluid (e.g., an undiluted whole blood sample) to a top layer of the device. According to some embodiments, the device is used by waiting < 5 minutes from the fluid application for at least a portion of the fluid to travel through the device and fill the second sample collection region. The device is, according to some embodiments, then dried and stored. The device may be stored for long-term downstream applications as discussed above, or for immediate application (e.g., immediate analyte detection via analytical methods). The ability to remove white blood cells specifically from fluids (e.g., whole blood) may provide a number of advantages for analyzing patient samples for a wide variety of red blood cell-focused diseases (e.g., several parasitic diseases including malaria) without contamination from unwanted white blood cells. Even applications such as determination of HIV viral load, where plasma is traditionally used rather than whole blood, the devices in this example could provide a valuable alternative to plasma separation cards. The devices provided in this example advantageously requires a minimal amount of whole blood (e.g., 50–100 µL) relative to other analytic techniques. In some embodiments, a device described herein may be used to obtain a variety of patient health information via downstream methods like qPCR. Moreover, a device described herein may have a relatively small footprint and low cost, making it advantageous for use in the field. A device according to the embodiments described herein may advantageously allow for whole blood collection and separation of white blood cells at point-of-care settings. A device as described herein may, in some embodiments, offer advantages for long-term storage for downstream applications (e.g., biobanking of emerging parasites). The size of and stacking of devices described in this example may provide a method of white blood cell separation from whole blood that is faster and easier to use then other separation methods, according to some embodiments. The separation may occur passively, e.g., (providing user-free separation of white blood cells). In some embodiments, devices and methods provided in this example can be used for microsampling of blood via lancet in remote or field settings or the home, without requiring a trained phlebotomist to collect large volumes of blood for transport via cold chain. A device may be configured to fill any of a wide variety of hematocrit ranges (e.g., 25– 55%) to accommodate different patients. In some embodiments, a device is configured to dry quickly (e.g., within 30 minutes). Quick drying may promote DNA stability. Drying may also provide the advantage of hematocrit-independent, single extraction punch volume across the tested hematocrit range to allow for matched liquid reference comparisons. Materials and Methods Chemical reagents and materials Munktell TFN paper was purchased from Laboratory Sales and Services (Somerville, NJ). Leukosorb sheets were purchased from Pall Corporation (Port Washington, NY). Fellowes and Avery laminates, and 6 mm hole punch were purchased from Amazon. 1∕4” clear acrylic sheets were purchased from McMaster-Carr. Sterile pipette tips were purchased from Mettler Toledo (Columbus, OH). 40-mm microhematocrit capillary tubes were purchased from LW Scientific. Samples of whole blood collected in potassium EDTA vacutainers were obtained from Research Blood Components (Watertown, MA). Drabkin’s reagent, Brij 35 (30% w / w), and ASTM Type I water were purchased from Ricca Chemical (Arlington, TX). Critoseal vinyl plastic putty and 2 mL microcentrifuge tubes were purchased from VWR. QiAamp DNA Mini kits were purchased from Qiagen (Germantown, MD). Whatman 903 Protein Saver cards were purchased from Fisher Scientific (Hampton, NH). 100% ethanol, 96-well qPCR plates, MicroAmp optical adhesive film, and Fast SYBR Green Master Mix were purchased from Thermo Fisher (Waltham, MA). β-actin forward (5’- CAC CAT TGG CAA TGA GCG GTT C- 3’) and reverse (5’- AGG TCT TTG CGG ATG TCC ACG T-3’) primers, and sbp1 forward (5’- GGC ATC TGC AAC TAC CGA AT-3’) and reverse (5’- GCT TGA AAA ACC GTC ATC GT- 3’) primers were purchased from Integrated DNA Technologies (Coralville, IA). Fabricating leukocyte depletion cards Four pDBS cards were designed in Adobe Illustrator (LDC 1–LDC 4). A double-sided wax transfer method was utilized to pattern the TFN with unique designs on each side. Briefly, the top and bottom designs were printed onto Avery laminate sheets using a Xerox ColorQube 8580 wax printer. Next, a sheet of TFN was aligned with the top and bottom designs using a custom acrylic alignment jig. Finally, a VEVOR P8200 T-shirt press (50 s at 142 °C) was employed to transfer the wax from the laminate sheets to the paper to form hydrophobic barriers through the full thickness of the paper. Leukosorb circles or channels were cut using a VEVOR SH-G35050W laser engraving machine (Rancho Cucamonga, CA). Each card was fabricated by attaching each layer with laser-cut adhesive sheets and sealed each card using Fellowes laminates. Measuring and adjusting the hematocrit from whole blood samples The initial hematocrit of each donor whole blood sample was measured upon arrival using previously described methods. Samples of whole blood at different hematocrit values (25– 55%) were created by adjusting the volume of native plasma in the sample. Hematocrit value was confirmed by measuring the hematocrit value as described above (n = 2 capillary tubes per contrived hematocrit). In vitro Plasmodium falciparum culture conditions P. falciparum strain NF54 was obtained through BEI Resources. In brief, parasites were maintained in an atmosphere of N2 / CO2 / O2: 90 / 5 / 5 and complete RPMI medium (RPMI 1640, 25 mM HEPES, 100 μg mL-1hypoxanthine, 0.3 mg mL-1glutamine (KD Biomedical, Columbia, MD)) supplemented with 25 mM NaHCO3 (pH 7.3), 5 μg / ml of gentamicin, and 10% human serum (Interstate Blood Bank, Memphis, TN) or 0.5% Albumax II (Gibco, Waltham, MA). Parasitemia (Infected RBCs / Total RBCs*100) was evaluated through microscopy after Giemsa staining of smears (10%, 15 minutes). Sorbitol treatment (5%, 10–30 min at 37 °C) was used to synchronize parasites in ring-stage. Making whole blood samples with contrived parasitemias to add to LDC 4 and 903 cards Sorbitol-synchronized ring stage parasites were harvested and the hematocrit was adjusted to 40% using culture medium. Using these adjusted 40% hematocrits, a range of 0%, 0.001%, 0.01%, 0.1%, 1% and 5% parasitemia was prepared. Calculations are shown below. 50 µL of each parasitemia dilution was applied to LDC 4 and 903 cards, and stored an additional 50 µL as a whole blood pellet. The devices, 903 filter paper as well as the same loading volume was also stored as a whole blood pellet. Five replicates were generated for each LDC 4 and 903 card at each parasitemia and one replicate was generated for each blood pellet at each parasitemia. Analyzing LDC 4 and 903 cards with contrived parasitemias LDC 4 and 903 cards were stored at 4 °C until analysis. Prior to analysis, samples were removed from their foil bags. For LDC 4 cards, a standard 6 mm hole punch was used to remove the extraction zone (n = 5 zones per card). For 903 cards, a5 / 8” manual punch was used to remove the entirety of each blood spot (n = 5 spots per card). gDNA was extracted from each punch and the liquid controls using a Qiagen QIAamp DNA Mini kit and according to Qiagen’s dried blood spot and liquid whole blood extraction protocols. 100 µL of Qiagen QIAamp DNA Mini Kit Buffer AE (water-based elution buffer) was used for the final elution step and the purified gDNA was stored at -20 °C until use. The β-actin and sbp1 genes were amplified from each purified DNA sample using a QuantStudio3 Real Time PCR system. Briefly, each 20 µL qPCR reaction mix contained 10 µL Fast SYBR Green Master Mix, 1.6 µL of mixed forward and reverse β-actin or sbp1 primers (5 µM total per reaction), 6.4 µL Type I water, and 2 µL of purified DNA. RNase P was used as the non-template control. Instrument cycling conditions are shown in FIG. 41. Clinical sample collection Approximately 1 mL of blood from each participant was collected. For each sample, five 50 μL drops of blood were spotted onto individually labeled Whatman 903 Protein Saver Cards and LDCs. Both card types were dried at room temperature. Upon drying, both card types were placed in a foil bag containing a desiccant and stored at room temperature pending analysis. The remaining blood samples were stored at -20oC. Determining parasite density of clinical samples using microscopy Blood films were processed and stained according to WHO guidelines. Two independent malaria microscopists read each smear, with any discordant calling of positive or negative smears broken by a third malaria microscopist. Parasite density was estimated as the number of parasites counted per 200 WBCs, multiplied by 40 based on the assumption that 1 μL of blood contains 8000 WBCs. Analyzing 903 cards and LDCs from clinical patient samples As more than one PCR plate was needed, a correction factor as described in equation 1 was employed to correct the measured parasite densities where Cq is cycle threshold (output of qPCR), Cqiis the cycle threshold for the sample on plate “i”, and Cqi-IPC is the Cq of the interpolate calibrator. Selective whole genome amplification gDNA was extracted from three types of clinical patient samples—samples stored on 903 cards, samples stored on LDCs, and matched liquid reference samples (n = 2 replicates per patient)—to selective whole genome amplification (sWGA). In brief, sWGA is an enrichment method to selectively amplify target genome (here Plasmodium falciparum DNA) over background DNA (human genome) using a pool of primers designed to amplify frequently occurring motifs of short nucleotides in P. falciparum reference genome. The sWGA experiment was performed in two steps. First, 8 µL of each purified gDNA sample, 0.25 µL (final solution concentration of 20 µM of each primer in the pool), 0.5 µL of 10X ThermoFisher EquiPhi29 reaction buffer, and 1.25 µL of nuclease-free water was combined. The resulting 10 µL for 3 minutes at 95º was then denatured. Next, the denatured product was then mixed with 1 µL (10 units) of EquiPhi29 DNA polymerase, 2 µL reaction buffer 0.2 µL of 100µM MDT, 2µL of 10mM dNTPs, and nuclease-free water to make a total pool volume of 20µL and isothermally amplified 45ºC for 3 hours, then 65ºC for 10 minutes to suspend further enzyme activity. Amplification success was validated with measuring DNA quantity before and after enrichment using Qubit. MIP sequencing and data analysis sWGA amplified DNA was targeted, captured, and sequenced using a molecular inversion probe (MIP) targeting key P. falciparum resistance genes associated with artemisinin and partner drug resistance, including pfkelch13, pfmdr1, pfcrt, pfdhfr and and pfdhps genes. MIP capture and library preparation was performed. In brief, sequencing using an Illumina NextSeq 550 instrument (150 bp paired-end reads) was conducted at Brown University (RI, USA). The raw data was generated using MIPs was demultiplexed using MIPtools software (https: / / github.com / bailey- lab / MIPTools), which is a computationally suitable tool for MIP data processing and analysis. In brief, the data was further processed using MIP Wrangler software (https: / / github.com / bailey- lab / MIPWrangler), in which sequence reads sharing the same Unique Molecular Identifiers (UMIs) were collapsed to generate a single consensus. Each dataset was then analyzed by mapping sequence reads to the P. falciparum 3D7 reference genome using Burrows-Wheeler Aligner (BWA) to generate a total number of sequenced reads per sample and sequencing coverage per samples per MIP probe used. The count was then compared (Figure 33A), coverage (Figure 33B), and read depth across different parasite densities for each sample set (903 card versus LDC) using R software, using a p-value of ≤ 0.05 as statistically significant. Example Embodiments FIGS. 11A-11B, 12A-12B, 13A-13B, and 14A-14B provide a few schematic illustrations and photographs of non-limiting devices, according to some embodiments. Some such devices may be referred to as leukocyte depletion cards (“LDCs”), cards, and / or prototypes. Four card prototypes were designed and tested: prototype 1 (Figure 11A-11B), prototype 2 (Figure 12A-12B), prototype 3 (Figure 13A-13B), and prototype 4 (Figure 14A-14B), with various differences in material for different purposes (e.g., to promote RBC movement while restricting WBC movement to the extraction punch zone). In some embodiments, the material of a device described herein may comprise a single layer or one or more layers. For example, as exemplary embodiments: Prototype 1: Bottom layer = TFN channel, top layer = 7 mm TFN circle Prototype 2: Bottom layer = TFN channel, top layer = 7 mm Leukosorb circle Prototype 3: Bottom layer = TFN channel, top layers = two 7 mm Leukosorb circles stacked on each other Prototype 4: Single layer of Leukosorb in the shape of the channel inlaid within a TFN support FIGS. 8-10 include data regarding qPCR quantification of human 18s rRNA (leukocyte) target, associated ΔCTvalues, and various parasitemia ranges using synchronized culture and whole blood. In some embodiments, a single layer of Leukosorb may be used as is or with additional treatments (e.g., to allow for faster drying and / or improve DNA / RNA stability). Each prototype was challenged with 50 µL of blood with contrived hematocrits of 25– 55%. All four prototypes filled the entirety of the extraction zone over the hematocrit range tested (Figures 11C, 12C, 13C, 14C). In some embodiments, the hematocrit ranges do not have a significant effect on the punch volume. A non-limiting example is shown in Table 4. This is believed to be advantageous because it may allow for the use of a single volume as a liquid reference for comparison to a sample from any subject by comparing the extracted liquid punches. Prototypes 1, 2, and 3 provided average punch volumes of 13.0, 18.4, and 9.7 µL, respectively (Figures 11D, 12D, 13D), across the hematocrit range (25–55%, FIG. 15); however, these numbers varied significantly between hematocrits (ANOVA, p < 0.001 for all three prototypes). The variation between average punch volumes and hematocrit range may be characterized through statistical parameters such as p values. For example, low p values may represent a high variation. In some embodiments, the average punch volume does not vary between hematocrit ranges (See FIGS. 11D, 12D, 13D, and 14D). For example, as shown in Figure 11D, prototype 4 provided an average punch volume of 9.0 µL that did not significantly vary between hematocrit ranges (p = 0.11). Prototype 3 did not provide hematocrit independence across the entire hematocrit range tested. Although prototype 3 did not provide hematocrit independence across the entire hematocrit range tested, it did provide hematocrit independence across 25–50% hematocrit (p = 0.06). Such embodiments may be suitable when the subject does not present a wide range of hematocrit ranges, such as when the subject is a malaria patient. To determine WBC loss afforded by prototypes 3 and 4, we quantified the number of WBCs in each sample via quantitative PCR (qPCR) using primers for β-actin, a common reference gene used when analyzing devices (see FIGS. 16A-16B for representative amplification and melt curve analysis). β-actin Cts from each card prototype punch were compared to a matched liquid reference volume: 50 µL, 9.7 µL, and 9.0 µL for the 903 card, prototype 3 and prototype 4, respectively (FIG. 17). Prototype 4 depleted significantly more WBCs than the 903 card (ANOVA, p < 0.001) and prototype 3 (p = 0.009). In vitro Plasmodium-infected blood with parasite counts of 0.001, 0.01, 0.1, 1, and 5% was contrived and applied 50 μL to the 903 card and LDC (n = 5 zones per parasitemia). WBC and parasite DNA (β-actin and spb1 genes, respectively) from punches and matched liquid reference volumes (50 µL and 9 µL for 903 card and LDC, respectively) were quantified via qPCR (FIG. 18), to determine parasite enrichment. Results indicate minimal parasite enrichment (fold change = 1.2) for the 903 card versus the liquid reference (FIGS. 19A-19B). Promisingly, we demonstrate improved fold change of 243.2 and 139.6 for LDC versus its liquid reference and versus the 903 card, respectively. Venous blood was obtained from 16 malaria-infected patients in Cape Coast, Ghana with cell and parasite counts ranging from 3,800–20,100 WBC μL-1 and 33–251,100 parasites μL-1, respectively (FIG. 20). 50 µL of each sample was applied to 903 cards and LDCs (n = 5 spots per card type per patient, FIG. 21 and FIG. 22). DNA was extracted from both cards and qPCR was performed thereon to obtain β-actin and sbp1 Ct values for each sample (FIGS. 23-24). Unlike in vitro samples, extracted DNA from clinical samples was run across multiple PCR plates. To normalize for plate-to-plate variability, a calibrator sample was employed. The Ct values from each plate were then normalized using the calibrator sample to obtain “corrected” Ct values and other Ct calculations (FIG. 25). To understand if the clinical samples followed similar Ct trends to in vitro samples, the sbp1 Ct values for in vitro and clinical samples were compared (FIGS. 26A-26C and 28A-28B). While a significant loss of parasites in the 903 card was observed by linear regression comparison analysis (ANCOVA, ɑ = 0.05, p = 0.002), no significant loss in parasites was observed for LDC (p = 0.497). The 903 card had a 1.2-fold change enrichment over the liquid reference while LDC had a 32.5-fold and 36.6-fold change enrichment (FIG. 27) over the liquid reference and 903 card, respectively. To understand why these values were lower clinically than in vitro, raw Ct values were converted into WBC and parasite counts using calibration curves (FIG. 27). WBC and parasite counts are reported as total counts per extracted sample (FIG. 29). The recovery of WBC cells and parasites from each card punch was then calculated using the liquid reference sample (FIGS. 30-31). FIG. 32 illustrates average recovery of WBCs and parasites from each card. Interestingly, both cards deplete WBCs (< 18% remaining for both cards); however, 903 cards also deplete parasites with an average of only 18% of parasites present in these samples. Since the entire 50 μL zone was extracted from the 903 card, there should be no parasite loss. This result highlights a problem with DNA stability in the 903 card. In contrast, LDC showed 126.2% parasite recovery, suggesting that LDC stabilizes DNA due to fast drying and may enrich parasites at the extraction zone. Using 3 of the 16 clinical samples (Patients 02, 09, and 11), the extracted Plasmodium DNA was amplified using selective whole genome amplification. Then, we sequenced the samples using molecular inversion probes and Illumina sequencing. Results show significant improvement in read counts (FIG. 33) for DNA extracted from LDC versus 903 cards for Patients 02 and 11. Some devices described herein provided an average 244-fold and 140-fold parasite enrichment over venous blood and the 903 card, respectively. These devices were tested clinically in Ghana using blood from 16 P. falciparum-infected patients (0.001–7.7% parasitemia). The devices afforded an average 32.5-fold and 36.6-fold parasite enrichment over venous blood and the 903 card. Interestingly, when results were converted to WBC and parasite counts per extraction zone, both cards depleted WBCs (11.4% and 17.2% recovery for 903 card and LDC, respectively). Some devices showed > 100% parasite recovery (126.2%), suggesting that these devices stabilizes DNA by fast drying and may enrich parasites at the extraction zone. Sequencing of 3 of the 16 patient samples (56, 4046, and 46,909 parasites µL-1) demonstrated a significant improvement in read counts and coverage for the middle and high parasitemias. A DBS card capable of storing patient blood while enriching the amount of Plasmodium genetic material in the extraction zone through restricting the movement of host WBCs is described herein. Initial sequencing data suggests the use of some LDCs described herein over the 903 card to improve monitoring parasites and determine drug resistance. EXAMPLE 2 In this example, various exemplary fluidic devices are described. In FIG. 34, exemplary fluidic devices (e.g., pDBS cards) having one or more layers are depicted. In some embodiments, such fluidic devices can be uses for applications related to the diagnosis and / or detection of malaria. Arrows in FIG. 34 indicate the position of the inlet allowing for a sample (e.g., a blood sample) to enter the fluidic device. The sample, according to some embodiments, may travel and / or flow along channels in the fluidic device. FIGS. 35A-35C shows a fluidic device having a first layer comprising laser cut TFN and a second layer comprising leukosorb. In some embodiments, the fluidic device is configured to receive a sample (e.g., a blood sample) FIG. 35D shows the results of Drabkin’s assay depicting the extraction zone volume and indicating that an analysis of variance shows no significant difference in extraction zone volume with samples having different hematocrits. FIGS. 36A-36B shows a fluidic device having a first layer comprising TFN and at least one layer comprising Leukosorb. FIG. 36C shows the results of a Drabkin’s assay indicating extraction zone volume as a function of the hematocrit of each sample tested. FIGS. 37 depicts the results fluidic devices in FIGS. 35A-35C and FIGS. 36A-36B as compared to a typical 903 card. For various samples having different hematocrits, the fluidic devices described herein generally have a lower ΔCt than the 903 Card, and moreover, the data in FIG. 37 shown that the fluidic devices (e.g., “Card A” and “Card B” in FIG. 37) deplete WBCs better than 903 cards. FIG. 38 show raw Ct values for liquid references including for the fluidic device of FIGS. 35A-35C and a 903 Card. Such data was derived from control experiments from samples of whole blood supplemented with RBCs infected with P. falciparum at different %parasitemia. Since the blood is from a single donor at a single hematocrit, very little change in the Ct of the human gene that was amplified (18sRNA) was expected, but there generally is a proportional change in the Ct from the malaria parasite gene (sbp1) as a function of parasitemia, in some embodiments. The slope of such relationship is close to -3.32 such that the overall amplification efficiency is close to 100%. The known volume in a sample for used to demonstrate the above prototypes was 9µL while the comparator (Whatman 903) was 50µL. Accordingly, the aforementioned experiments compare and / or describe efficiencies of removal of those volumes of samples that are dried on these devices. FIG. 39 shows the results of an analysis of the Ct value between extraction zones and liquid references in the fluidic device of FIG. 35A-35C. Briefly, the data shows the ability of the fluidic device to remove WBC from the extraction zone. Such an ability is desirable especially if a ΔCt, 18S value greater than 0. The data also shows the ability of the fluidic device to allow RBCs to flow to the extraction zone. Such an ability is desirable especially if a ΔCt, sbp1 value less than or equal to 0. As shown in FIG. 37, the fluidic device depicted in FIGS. 35A-35C (“Card B”) appears to have a greater ΔCt, 18S values and lower ΔCt, sbp1 values than the Whatman 903 card at various parasitemia concentrations. Such results may indicate that the fluidic device of FIGS. 35A-35C remove more WBCs from the extraction zone and allow for more RBCs to flow to the extraction zone compared to the 903 Card. FIG. 40 compare the WBC depletion and iRBC movement abilities between the fluidic device of FIGS. 35A-35C (“Card B”) and the Whatman 903 card. Briefly, Card B enriches iRBCs, on average, 58-fold better than liquid samples and 78-fold better than 903 cards. While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present invention is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and / or methods, if such features, systems, articles, materials, and / or methods are not mutually inconsistent, is included within the scope of the present invention. The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and / or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc. As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law. As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc. As used herein, “wt%” is an abbreviation of weight percentage. As used herein, “at%” is an abbreviation of atomic percentage. Some embodiments may be embodied as a method, of which various examples have been described. The acts performed as part of the methods may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include different (e.g., more or less) acts than those that are described, and / or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above. Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMS What is claimed is:

1. A fluidic device, comprising: a first layer comprising a porous material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region; and wherein, upon application of a fluid comprising white blood cells and red blood cells to the first sample reception region, the porous material is configured to retain at least 75% of white blood cells upstream from the second sample reception region and allow transport of the red blood cells to the second sample reception region via the channel.

2. A method of determining a property of a blood sample, comprising: transporting a fluid comprising white blood cells and red blood cells through a channel from a first sample reception region to a second sample reception region, wherein at least 75% of the white blood cells are retained upstream from the second sample reception region and a portion of the red blood cells is retained in or on the second sample reception region.

3. A fluidic device, comprising: a first layer comprising a porous material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region; and wherein, upon application of a fluid comprising white blood cells and pathogens to the first sample reception region, the porous material is configured to retain at least 75% of white blood cells upstream from the second sample reception region and allow transport of the pathogens to the second sample reception region via the channel.

4. A method of determining a property of a blood sample, comprising:transporting a fluid comprising white blood cells and pathogens through a channel from a first sample reception region to a second sample reception region, wherein at least 75% of the white blood cells are retained upstream from the second sample reception region and a portion of the pathogens is retained in or on the second sample reception region.

5. A fluidic device, comprising: a first layer comprising a porous material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region, wherein: the second sample reception region is positioned along the channel greater than or equal to 10 mm away and less than or equal to 30 mm from the first sample reception region, the channel has a length greater than or equal to 10 mm and less than or equal to 42 mm, the channel has a thickness greater than or equal to 0.4 mm and less than or equal to 0.8 mm, the channel has a width greater than or equal to 2 mm and less than or equal to 10 mm, and the channel has a porosity greater than or equal to 50 and less than or equal to 90%.

6. A method of determining a property of a blood sample, comprising: transporting a fluid comprising white blood cells and red blood cells through a channel from a first sample reception region to a second sample reception region, wherein: the second sample reception region is positioned along the channel greater than or equal to 10 mm away and less than or equal to 30 mm from the first sample reception region, the channel has a length greater than or equal to 0.1 mm and less than or equal to 42 mm,the channel has a thickness greater than or equal to 0.4 mm and less than or equal to 0.8 mm, the channel has a width greater than or equal to 2 mm and less than or equal to 10 mm, and the channel has a porosity greater than or equal to 50 and less than or equal to 90%.

7. A method of determining a property of a blood sample, the method comprising: transporting a blood sample comprising a plurality of white blood cells and a plurality of red blood cells through a fluidic device to a first region and a second region, wherein the second region is a sample reception region, wherein at least a first portion of the fluid is retained in or on the first region and a second portion of the fluid is retained in or on the second region, wherein the first portion of the fluid is enriched in white blood cells, and wherein the second portion of the fluid is enriched in red blood cells; and assaying the first region or the second region.

8. A fluidic device, comprising: a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region; and a second layer, wherein the second layer comprises a vertical transport region in fluidic communication with the first sample reception region and the second sample reception region, and wherein the first layer and / or the second layer comprises a nucleic acid stabilizer.

9. A fluidic device, comprising: a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, wherein the channel places the first sample reception region in fluidic communication with the second sample reception region, and wherein the first layer comprises a nucleic acid stabilizer.

10. A method, comprising: laterally transporting a fluid comprising a plurality of cells through a channel, wherein: the channel is positioned in a first layer comprising a porous, absorbent material, the first layer further comprises a first sample reception region and a second sample reception region, the channel places the first sample reception region in fluidic communication with the second sample reception region, and the first layer comprises an RNA stabilizer.

11. A method of determining a bloodborne pathogen, the method comprising: transporting a fluid comprising a plurality of white blood cells and a plurality of red blood cells through a fluidic device to a first region and a second region, wherein the second region is a sample reception region, wherein at least a first portion of the fluid is retained in or on the first region and a second portion of the fluid is retained in or on the second region, wherein the first portion of the fluid is enriched in white blood cells, and wherein the second portion of the fluid is enriched in red blood cells; and assaying the first region or the second region for the bloodborne pathogen.

12. A fluidic device, comprising: a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, wherein the channel places the first sample reception region in fluidic communication with the second sample reception region, and wherein the porous, absorbent material is configured to transport red blood cells therethrough to a higher degree than white blood cells.

13. A fluidic device, comprising:a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, and wherein the channel places the first sample reception region in fluidic communication with the second sample reception region; and a second layer, wherein the second layer comprises a vertical transport region in fluidic communication with the first sample reception region and the second sample reception region, and wherein the first layer and / or the second layer comprises an RNA stabilizer.

14. A fluidic device, comprising: a first layer comprising a porous, absorbent material, wherein the first layer comprises a channel, a first sample reception region, and a second sample reception region, wherein the channel places the first sample reception region in fluidic communication with the second sample reception region, and wherein the first layer comprises an RNA stabilizer.

15. A method, comprising: laterally transporting a fluid comprising a plurality of cells through a channel, wherein: the channel is positioned in a first layer comprising a porous, absorbent material, the first layer further comprises a first sample reception region and a second sample reception region, the channel places the first sample reception region in fluidic communication with the second sample reception region, and the first layer comprises a nucleic acid stabilizer.

16. The fluidic device or method of any one of the preceding claims, wherein the porous material has a median pore size of greater than or equal to 5 micrometers and less than or equal to 40 micrometers.

17. The fluidic device or method of any one of the preceding claims, wherein the porous material has a thickness of greater than or equal to 300 micrometers and less than or equal to 700 micrometers.

18. The fluidic device or method of any one of the preceding claims, wherein the porous material is Leukosorb.

19. The fluidic device or method of any one of the preceding claims, wherein white blood cells are immobilized in the porous material and red blood cells are capable of flowing through the porous material.

20. The fluidic device or method of any one of the preceding claims, wherein a 50 microliter sample provided to the first sample reception region is capable of drying within 60 minutes while in an environment having a relative humidity of 40%, and wherein the sample has a hematocrit of greater than or equal to 25% and less than or equal to 55%.

21. The fluidic device or method of any one of the preceding claims, wherein the porous material allows for greater than 80% of the red blood cells in the fluid to flow through the device away from the first sample reception region.

22. The fluidic device or method of any one of the preceding claims, wherein the porous material comprises polyester.

23. The fluidic device or method of any one of the preceding claims, wherein the porous material comprises a white blood cell filter.

24. The fluidic device or method of any one of the preceding claims, wherein the channel extends beyond the second sample reception region.

25. The fluidic device or method of any one of the preceding claims, wherein the first and / or the second sample reception regions are configured to contain a volume at least 40 microliters and less than or equal to 70 microliters of a fluid sample.

26. The fluidic device or method of any one of the preceding claims, wherein the second sample reception region is positioned along the channel such that a portion of the red blood cells in the sample is distributed on the second sample reception region such that the concentration of the red blood cells in the second sample region is greater than or equal to 80% and less than or equal to 120% of the concentration of the red blood cells at another position along the channel outside the second sample reception region.

27. The fluidic device or method of any one of the preceding claims, wherein the porous material comprises a porous, absorbent material.

28. The fluidic device or method of any one of the preceding claims, wherein the second portion of the fluid is enriched in the bloodborne pathogen, if originally present in the fluid, and wherein the method comprises assaying the second region for the bloodborne pathogen.

29. The fluidic device or method of any one of the preceding claims, wherein the blood sample is a whole blood sample.

30. The fluidic device or method of any one of the preceding claims, wherein the bloodborne pathogen is malaria.

31. The fluidic device or method of any one of the preceding claims, further comprising drying the first sample reception region and / or the second sample reception region.

32. The fluidic device or method of any one of the preceding claims, further comprising recovering RNA from the first sample reception region and / or the second sample reception region at least a month after the lateral transport of the fluid.

33. The fluidic device or method of any one of the preceding claims, wherein the device is configured to stabilize RNA such that it can be recovered after a period of greater than or equal to 1 month of drying the device.

34. The fluidic device or method of any one of the preceding claims, further comprising malarial RNA.

35. The fluidic device or method of any one of the preceding claims, wherein the device is configured such that, when exposed to a volume of whole blood that is greater than or equal to a volume of the channel and that has a hematocrit value of greater than or equal to 25% and less than or equal to 55%, the whole blood fills both the first and second sample reception regions.

36. The fluidic device or method of any one of the preceding claims, wherein the device is configured such that, when exposed to a volume of whole blood that has a hematocrit value of greater than or equal to 25% and less than or equal to 55%, the amount of the second sample reception region filled by the whole blood is substantially independent of the hematocrit value.

37. The fluidic device or method of any one of the preceding claims, wherein the device includes exactly one layer, and wherein the exactly one layer is the first layer.

38. The fluidic device or method of any one of the preceding claims, wherein the device comprises a second layer, and wherein the second layer comprises a white blood cell filter in fluidic communication with the channel.

39. The fluidic device or method of any one of the preceding claims, wherein the white blood cell filter is positioned between an environment external to the fluidic device and the channel.

40. The fluidic device or method of any one of the preceding claims, wherein the porous, absorbent material is a white blood cell filter.

41. The fluidic device or method of any one of the preceding claims, wherein the device comprises a second layer comprising a first white blood cell filter and the porous, absorbent material is a second, different white blood cell filter.

42. The fluidic device or method of any one of the preceding claims, wherein the first layer and / or the second layer comprises a nucleic acid stabilizer.

43. The fluidic device or method of any one of the preceding claims, wherein the nucleic acid stabilizer is an RNA stabilizer.

44. The fluidic device or method of any one of the preceding claims, wherein the nucleic acid stabilizer is a DNA stabilizer.

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