Usefulness of optical density values from heparin-platelet factor 4 antibody testing and probability scoring models to diagnose heparin-induced thrombocytopenia.
Heparin-induced thrombocytopenia (HIT) is a complication caused by antibodies directed to the heparin-platelet factor 4 (PF4) complex with a seemingly paradoxical high risk of thrombosis. Discontinuation of heparin and administration of an alternative anticoagulant is important in prevention of catastrophic thrombosis. Diagnosis is challenging and based on clinical probability models (Warkentin 4 Ts and Chong scale) and, to a lesser degree, laboratory testing. Enzyme-linked immunosorbent assay (ELISA) measurement of heparin-PF4 antibodies is commonly used but has low predictive values for thrombosis. We analyzed 105 cases of suspected HIT and compared optical density values and the Warkentin 4 Ts for sensitivity, specificity, positive predictive value, and negative predictive value (NPV). The predictive value of ELISA alone was inferior to the Warkentin 4 Ts score. The sensitivity and NPV of the clinical score was improved by incorporating ELISA results. The combination of a negative ELISA result with low probability 4 Ts resulted in an NPV of 94%.
Janatpour
Kim A
KA
Department of Pathology, University of California, Davis Medical Center, Sacrament, CA 95817, USA.
Gosselin
Robert C
RC
Dager
William E
WE
Lee
Andrew
A
Owings
John T
JT
Zhou
Jufen
J
Wun
Ted
T
D000704:Analysis of Variance; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use; D001323:Autoantibodies / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000706:statistics & numerical data; D006493:Heparin / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D010978:Platelet Factor 4 / Q000276:immunology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013921:Thrombocytopenia / Q000097:blood / Q000139:chemically induced / Q000175:diagnosis*; D013927:Thrombosis / Q000188:drug therapy
D000925:Anticoagulants; D001323:Autoantibodies; D010978:Platelet Factor 4; D006493:Heparin