Diagnostic value of two immunoassays for detecting heparin/PF4 complex antibodies in heparin-induced thrombocytopenia / 中华血液学杂志

Objectives: To assess the diagnostic values of latex immunoturbidimetric assay (LIA) and particle immunofiltration assay (PIFA) for heparin-induced thrombocytopenia (HIT) . Methods: Samples from 94 patients with suspected HIT from May 2016 to July 2018 in our hospital were prospectively analyzed by the two immunoassays. Their medical records and further follow-up data were also collected and analyzed by our hematologists to make the 4Ts scores and confirm the diagnosis of HIT, respectively. Performance characteristics of the two immunoassays were assessed, including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) . Their post-test probabilities (PTP) were also calculated based on the 4Ts score. Results: Among 94 cases, 15 (16.0%) had a positive HIT, including 6 of 37 (16.2%) with an intermediate, and 9 of 15 (60.0%) with a high 4Ts score. PIFA operating characteristics were: sensitivity 100.0% (15/15) , specificity 51.9% (41/80) , PPV 28.3% (15/53) , NPV 100.0% (41/41) . The positive PTP in intermediate and high 4Ts score group were 28.7% and 75.7%, respectively, while negative PTP were all 0. At manufacturers' cutoffs, LIA operating characteristics were: sensitivity 66.7% (10/15) , specificity 94.9% (75/79) , PPV 71.4% (10/14) and NPV 93.8% (75/80) . The positive and negative PTP in intermediate 4Ts score group were 71.8% and 6.3%, while 95.2% and 34.4% in high 4Ts score group, respectively. Receiver operating characteristic (ROC) analysis manifested that LIA was preferable than PIFA, and combining the 2 assays together was significantly better than single test. Conclusions: 4Ts score is still an important tool for the diagnosis of HIT. Combining clinical score with heparin/PF4 antibody assay can increase the accuracy of confirming or excluding HIT. Although PIFA is inferior to LIA in the diagnostic value, its user friendliness and 100% NPV have major advantages. Combining the 2 assays together can achieve a higher diagnostic value.

Diagnostic value of two immunoassays for detecting heparin/PF4 complex antibodies in heparin-induced thrombocytopenia / 中华血液学杂志

Objectives@#To assess the diagnostic values of latex immunoturbidimetric assay (LIA) and particle immunofiltration assay (PIFA) for heparin-induced thrombocytopenia (HIT) .@*Methods@#Samples from 94 patients with suspected HIT from May 2016 to July 2018 in our hospital were prospectively analyzed by the two immunoassays. Their medical records and further follow-up data were also collected and analyzed by our hematologists to make the 4Ts scores and confirm the diagnosis of HIT, respectively. Performance characteristics of the two immunoassays were assessed, including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) . Their post-test probabilities (PTP) were also calculated based on the 4Ts score.@*Results@#Among 94 cases, 15 (16.0%) had a positive HIT, including 6 of 37 (16.2%) with an intermediate, and 9 of 15 (60.0%) with a high 4Ts score. PIFA operating characteristics were: sensitivity 100.0% (15/15) , specificity 51.9% (41/80) , PPV 28.3% (15/53) , NPV 100.0% (41/41) . The positive PTP in intermediate and high 4Ts score group were 28.7% and 75.7%, respectively, while negative PTP were all 0. At manufacturers’ cutoffs, LIA operating characteristics were: sensitivity 66.7% (10/15) , specificity 94.9% (75/79) , PPV 71.4% (10/14) and NPV 93.8% (75/80) . The positive and negative PTP in intermediate 4Ts score group were 71.8% and 6.3%, while 95.2% and 34.4% in high 4Ts score group, respectively. Receiver operating characteristic (ROC) analysis manifested that LIA was preferable than PIFA, and combining the 2 assays together was significantly better than single test.@*Conclusions@#4Ts score is still an important tool for the diagnosis of HIT. Combining clinical score with heparin/PF4 antibody assay can increase the accuracy of confirming or excluding HIT. Although PIFA is inferior to LIA in the diagnostic value, its user friendliness and 100% NPV have major advantages. Combining the 2 assays together can achieve a higher diagnostic value.

The incidence of heparin-induced thrombocytopenia and positivity of antibody in patients treated with heparin preparations / 中华内科杂志

Objectives To investigate the incidence of the heparin-induced thrombocytopenia (HIT) and positivity of anti-heparin/platelet factor 4 complex antibody (HIT-antibody) in inpatients treated with heparin preparations.Methods A total of 197 consecutive patients,including 120 men and 77 women,who were treated with unfractioned heparin (UFH) or low molecular weight heparin (LMWH),were enrolled in this study.HIT-antibody was detected by enzyme-linked immunosorbent assay (ELISA).All patients were classified into subgroups based on 4Ts (Pretest Clinical Scoring System) and types of underlying disorders.The incidence of HIT and positivity of HIT-antibody among different groups were analyzed.Results The overall incidence of HIT was 3.0％ (6/197),and the positivity of HIT antibody was 12.2％ (24/197).The positivity of HIT-antibody was 10.1％ (18/178),7.7％ (1/13) and 83.3％(5/6) in low,moderate and high HIT probability group respectively.There were significant differences of HIT positivity and mean level of HIT-antibody between the high HIT probability group and the low or moderate HIT probability group (P =0.000).Both the incidence of HIT and positivity of HIT-antibody were higher in surgical patients than in medical patients (5.8％ vs 0.9％,P =0.047 and 19.8％ vs 6.3％,P =0.004).Conclusions The incidence of HIT and positivity of HIT-antibody were 3.0％ and 12.2％ respectively,both of which were related with the types of disorders.Detection of HIT-antibody has a better applicable value in patients with high HIT probability.