A novel PF4-dependent p-selectin expression assay (PEA) has proven effective in detecting platelet-activating heparin-induced thrombocytopenia and thrombosis (HIT) antibodies, according to research presented at the 57th ASH Annual Meeting.
These antibodies preferentially recognize heparin/platelet factor 4 (H/PF4) bound to platelet glycosaminoglycans in the absence of heparin, the researchers, led by Anand Padmanabhan, MBBS, MA, PhD, of the Medical Sciences Institute at the BloodCenter of Wisconsin, explained.
Dr. Padmanabhan and colleagues compared the diagnostic performance of PEA versus the serotonin release assay (SRA), which is considered the gold standard for HIT testing. Ninety-one serum samples from patients referred for HIT testing (with clinical scores ranging from 0 to 8) were tested using both assays. Samples were considered HIT-positive if patients had intermediate or high 4T scores and PF4 ELISA optical density (OD) values >1; samples were considered HIT-negative if patients had intermediate to high 4T score with PF4 ELISA OD <1.
Overall, PEA had greater accuracy for identification of samples from HIT-positive patients compared with SRA (0.93 vs. 0.82; p=0.01). "PEA has many attractive features, including its technical simplicity and its ability to allow physicians to identify patients suspected of having a high likelihood of HIT, suggesting that its use may facilitate early diagnosis and improve management of this diagnostically challenging disorder," the authors concluded.
Source: Padmanabhan A, Jones C, Curtis BR, et al. A novel PF4-dependent platelet activation assay identifies patients likely to have heparin-induced thrombocytopenia/thrombosis (HIT). Abstract #764. Presented at the 2015 ASH Annual Meeting, December 7, 2015; Orlando, Florida.