Evaluation of a New Nanoparticle-Based Lateral-Flow Immunoassay for the Exclusion of Heparin-Induced Thrombocytopenia (HIT),

Heparin-induced thrombocytopenia (HIT) is an adverse complication of heparin caused by HIT antibodies (abs) that recognize platelet factor 4-heparin (PF4/hep) complexes. Several laboratory tests are available for the confirmation and/or refutation of HIT. A reliable and rapid single-sample test is still pending. Objectives: To evaluate a new lateral-flow immunoassay based on nanoparticle technology. Patients/methods: A cohort of 452 surgical and medical patients suspected of having HIT was evaluated. All samples were tested in two IgG-specific ELISAs, in a particle gel immunoassay (PaGIA) and in a newly developed lateral-flow immunoassay (LFI-HIT) as well as in a functional test (HIPA). Clinical pre-test probability was determined using 4T's score. Results: Platelet-activating antibodies were present in 34/452 patients, all of whom had intermediate to high clinical probability. PF4/hep abs were detected in 79, 87, 86, and 63 sera using the four different immunoassays. The negative predictive values (NPV) were 100% for both ELISA tests and LFI-HIT but only 99.2% for PaGIA. There were less false positives (n=29) in the LFI-HIT compared to any other test. Additionally, significantly less time was required to perform LFI-HIT (median time, 11 min 30 sec) than to perform the other immunoassays. Conclusion: A newly developed lateral-flow assay, LFI-HIT, was capable of identifying all HIT patients in a cohort in a short period of time. Beside an NPV of 100%, the rate of false-positive signals is significantly lower with LFI-HIT than with other immunoassay(s). These performance characteristics suggest a high potency in reducing the risk and costs in patients suspected of having HIT.

No relevant conflicts of interest to declare.