comparison of polyspecific versus igg specific elisa in predominately cardiac patients with suspected heparin induced thrombocytopenia

A diagnosis of heparin induced thrombocytopenia (hit) must often be made based on clinical and laboratory evidence. this was a quasi-experimental study of patients admitted from 2016 to 2017. the primary endpoint was the incidence of false positive results in polyspecific and igg specific enzyme-linked immunosorbent assay (elisa); then we compared the sensitivity and specificity of each assays in predominately cardiac patients with suspected hit. a sensitivity/specificity analysis was conducted using serotonin release assay (sra) as the ‘gold standard’. the secondary outcome measures included length of hospital stay. we identified a total of 155 patients who met the inclusion criteria. confirmatory tests with sra on both groups were completed; false positive result was higher in the polyspecific group when compared to the igg group [60% vs. 5%]. the igg specific elisa test yielded a sensitivity of 100% and a specificity of 95% however, the polyspecific elisa had a low yield for specificity of 24% but maintained 100% sensitivity. in the igg specific group with hit-, their median length of stay was halved compared to those who were hit + ; hospital los in days, iqr [30 (27–81) vs. 15 (7–33) p = 0.023] and a shorter median los in the icu, iqr [24 (5–47) vs. 6 (2–14); p = 0.079]. hospital or icu los was the same in both (hit+ and hit−) groups managed with polyspecific elisa. the igg specific test had few false positive results and a high sensitivity score. ensuring appropriate testing can bring a substantial decrease in drug expenditure, reduced length of stay and prevent unnecessary anticoagulation.