Automated immunoassays of heparin induced thrombocytopenia antibodies is superior to the 4T′s score in HIT diagnostic efficacy / 中华检验医学杂志

ABSTRACT

Objective To discuss the diagnostic value of HIT-antibodies in suspected HIT patients with heart diseases.Methods A single center study.We collected 242 blood samples of suspected HIT patients whose platelet count decreased after heparin application during July 1 st ,2012 to June 30th ,2016 in Wuhan Asia Heart Hospital and detected the concentration of HIT antibodies , meanwhile the 4T′s score were calculated.Among the study objects , there are 206 patients received cardiac surgery , 28 received cardiac interventional therapy and 8 received drug therapy.And we divided them into HIT group (44, median age 57.5, 23 females ) and non-HIT group ( 198, median age 63.5, 87 females ) according to clinical diagnosis.Quantitative data was analyzed by independent t-test or Mann-Whitney U test.Qualitative data was analyzed by Fisher′s exact test.We drew ROC curve according to the statistical analysis to determine the optimal threshold value of antibodies in diagnosis of HIT andsensitivity , specificity, negative likelihood ratio, positive likelihood ratio of the HIT antibody detection .Therefore, we can assess the value of HIT antibody detection in HIT clinical diagnosis and treatment .Moreover, we used the optimal threshold value of antibodies to testify the suspected HIT patients .Results The HIT antibody concentration of HIT group (44) and non-HIT group ( 198 ) are 3.2 ( 95% CI1.8 -5.5 ) U/ml and 0.4 ( 95% CI0.3 -0.4 ) U/ml, respectively.The concentration of HIT group is much higher than the non-HIT group(P<0.000).When the cut-off value of HIT-Ab is set at 0.9 U/ml, sensitivity and specificity are 93.2%and 91.9%, respectively. And negative likelihood ratio and positive likelihood ratio are 0.07 and 11.53, respectively.When the cut-off value of HIT-Ab is set at 0.6 U/ml, sensitivity and specificity are 100.0%and 73.7%.HIT-Ab and 4T′s score of ROC-AUC are 0.971 and 0.745, respectively.The diagnosis value of HIT-Ab in HIT is significantly higher than the 4T′s score ( P<0.000).Conclusions HIT antibody detection is a simple and effective auxiliary diagnostic method in HIT exclusion .And HIT antibody detection is more optimal than the 4T′s score in HIT diagnosis and treatment .