The enumeration of cells in fluids by
flow cytometry is widely used across many disciplines such as assessment of leukocyte subsets in different bodily fluids or of bacterial
contamination in environmental samples,
food products and bodily fluids. For many applications the cost, size and complexity of the instruments prevents wider use, for example, CD4 analysis in HIV monitoring in resource-poor countries. The novel device, methods and
system disclosed herein largely overcome these limitations. The
system includes a simple
system for CD4 and CD8 counting in point-of-care HIV staging within
resource poor countries. Unlike previous approaches, no
sample preparation is required with the sample added directly to a
chip containing dried reagents by capillary flow. A large area image cytometer consisting of an LED module is used to excite the fluorochromes PerCP and APC labeled targets and a
monochrome CCD camera with a combination of two
macro lenses captures images of 40 mm2 of blood (approximately 1 microliter). CD4 and CD8-T-
lymphocyte counts correlate well with those obtained by
flow cytometry. The cytometer system described in the present invention provides an affordable and easy-to-use technique for use in remote locations.