A Straightforward Detection of HIT Type II via QCM-D

Abstract

Heparin Induced Thrombocytopenia (HIT) is an undesired antibody based immune reaction against complexes of platelet factor 4 and heparin. HIT occurs in patients receiving heparin as anticoagulant over several days and is connected to the risk of life threatening thrombosis through intravasal platelet aggregation. HIT antibodies are routinely detected by Enzyme Linked Immunosorbent Assay (ELISA). However, not all antibodies lead to platelet aggregation and therefore, to clinical problems. The clinical relevance of a HIT ELISA positive serum can be confirmed by functional tests for platelet activation, like the heparin induced platelet activation (HIPA) test. However, these tests are tedious and cumbersome. Therefore, we present a straightforward approach by applying quartz crystal microbalance technology for functional assays for diagnosis of HIT type II. We utilized the qCell T (quartz crystal microbalance with dissipation (QCM-D)) platform of 3T analytik, Tuttlingen, Germany to demonstrate platelet aggregation measurements induced by clinically relevant HIT positive type II sera of patients. During the measurements changes in frequency and dissipation were recorded. This revealed statistically significant differences between high and low dose measurements in both, PRP and washed platelets. Platelet adhesion to the sensor surfaces was visualized by scanning electron microscopy (SEM). QCM-D data was in good accordance to SEM images. The results presented here promising that in the future specially adapted QCM-D sensors could be a serious straight forward alternative to currently used functional HIT assays.