Usefulness of optical density values from heparin-platelet factor 4 antibody testing and probability scoring models to diagnose heparin-induced thrombocytopenia

Kim A. Janatpour, Robert C. Gosselin, William E. Dager, Andrew Lee, John T Owings, Jufen Zhou, Theodore Wun

Research output: Contribution to journalArticle

31 Scopus citations


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%.

Original languageEnglish (US)
Pages (from-to)429-433
Number of pages5
JournalAmerican Journal of Clinical Pathology
Issue number3
StatePublished - Mar 2007



  • Enzyme-linked immunosorbent assay
  • Heparin
  • Optical density
  • Thrombocytopenia
  • Thrombosis

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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