Methods and kits for detecting heparin/platelet factor 4 antibodies

Abstract

Methods for determining the presence of heparin / platelet factor 4 antibodies in a sample suspected to contain heparin / platelet factor 4 antibodies are provided, along with apparatus suitable for performing the methods. The method depends upon a color visualization indicating the presence or absence of heparin / platelet factor 4 antibodies in the sample. Preferred methods comprise contacting the sample with particles being complexed to platelet factor 4 (PF4) and which particle-complexed PF4 reacts specifically with heparin / platelet factor 4 antibodies, passing the sample / particle mixture through a filter, and then analyzing the color of the filtrate. The presence of heparin / platelet factor 4 antibodies in the sample is established where the color of the filtrate is substantially different from the color of the receptor-bearing particles.

Description

1. FIELD OF THE INVENTION [0001] The present invention relates to methods and kits useful for detecting heparin-induced thrombocytopenia (HIT) in a subject suspected of having HIT. In particular, the invention relates to methods and kits for the detection of heparin / platelet factor 4 antibodies in a sample by particulate immunofiltration assays, which are faster, simpler, and less expensive to operate than those previously known in the art. 2. BACKGROUND OF THE INVENTION [0002] Thrombocytopenia is a disorder in which the number of platelets in the blood is abnormally low. Drug-induced immune thrombocytopenia is a condition where the use of certain drugs leads to the formation of antibodies against platelets. These antibodies can cause a decrease in platelet count, resulting in the potential for increased bleeding and decreased ability for clotting. If these antibodies are formed during pregnancy, they may pass from the mother to the fetus. [0003] Heparin is the most widely used intr...

AI Technical Summary

Benefits of technology

[0008] To achieve the aforementioned objectives, the inventors have invented methods and kits for detecting heparin / platelet factor 4 antibodies in a variety of substances. The methods and kits depend upon a color visualization methodology indicating the presence or absence of heparin / platelet factor 4 antibodies. Preferably, the color visualization does not require the use of complicated instrumentation or equipment such that all color changes are readily detected by the naked human eye.

[0020] In specific embodiments, the PF4 complexed to the particles reacts specifically with heparin / platelet factor 4 antibodies such that the particles have the capacity to form aggregates upon contacting heparin / platelet factor 4 antibodies. The particles are incubated with the sample for a length of time sufficient for aggregates to form, preferably for about 5 minutes. More preferably, a reaction enhancer solution is added to the sample / particles mixture to optimize speed and sensitivity of the aggregation reaction.

[0038] In one embodiment, the wicking means comprises a polymeric material. In a specific embodiment, the wicking membrane comprises non-woven fibers of glass or synthetic polymeric material. In a preferred embodiment, the wicking membrane comprises polyester. In preferred embodiments, the wicking means separates a majority of any unaggregated particles from any non-specifically aggregated particles and / or any aggregates. In specific embodiments, the wicking means separates about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, or all unaggregated particles from any non-specifically aggregated particles and / or any specific aggregates. In a preferred embodiment, the wicking means separates more than 90% of unaggregated particles from any non-specifically aggregated particles and / or any specific aggregates. Preferably, the unaggregated particles migrate horizontally through the wicking membrane at a rate faster than the non-specifically aggregated particles and specific aggregates. In a specific embodiment, the unaggregated particles migrate horizontally through the wicking membrane at a rate from about 2 to about 10 times (i.e., 2, 3, 4, 5, 6, 7, 8, 9, and 10) faster than the non-specifically aggregated particles or specific aggregates. In a preferred embodiment, the unaggregated particles migrate horizontally through the wicking membrane at a rate greater than 10 times (e.g., greater than 10, 11, 12, 13, 14, 15, 20, 30, 50, 100, etc.) faster than the non-specifically aggregated particles or specific aggregates.

Problems solved by technology

These antibodies can cause a decrease in platelet count, resulting in the potential for increased bleeding and decreased ability for clotting.

The hallmark symptoms of Type II HIT are a drastic fall in platelet count and thrombosis, which can lead to limb gangrene (requiring leg amputation) or even death.

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