title: Heparin-induced thrombocytopenia testing is over-utilized in cirrhosis & correlates with poor clinical outcomes.
abstract: BACKGROUND
  Heparin-induced thrombocytopenia (HIT) is a serious complication seen in hospitalized, medically-ill patients. Evaluation for HIT using a commercially-available ELISA-based test has become increasingly common; however, it does have a high false positive rate. Implications of HIT testing in patients with cirrhosis have not yet been reported.
  
  
  METHODS
  We conducted a single-institution, retrospective review of all patients with cirrhosis admitted over a 29-month period. The student's t-test and the χ2 test were used for comparisons. We performed a stratified survival analysis using Kaplan-Meier and log rank testing.
  
  
  RESULTS
  A total of 1,305 patients had a HIT Ab sent during the study period. Of these patients, 106 had cirrhosis and were included in the study. Eighteen (17%) of the patients with cirrhosis were HIT Ab positive and four of the eighteen had a positive Serotonin Release Assay (SRA) confirmatory test. No difference was found in platelet nadir, thrombotic rate, length of stay, and patient survival between patients with positive HIT Ab and negative HIT Ab testing. No consistent treatment was used among patients who were HIT Ab positive, despite hematology service consultation. Patients who were HIT Ab negative were more likely to have undergone liver transplantation compared to those who were positive (27 vs. 5.5%, respectively; p = 0.048).
  
  
  CONCLUSIONS
  Our data suggest that HIT Ab testing is over-used in patients with cirrhosis and is poorly predictive of outcomes. With a poor positive predictive value, HIT testing may add unnecessary complexity to an already complicated patient population.
authors.affiliation: Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL. EUA.
authors.forename: Karlyn
authors.initials: K
authors.lastname: Martin
authors.affiliation: Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL. EUA.
authors.forename: Leila
authors.initials: L
authors.lastname: Kia
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of Michigan Health System, Ann Arbor, MI. EUA.
authors.forename: Neehar D
authors.initials: ND
authors.lastname: Parikh
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago IL. EUA.
authors.forename: Laura
authors.initials: L
authors.lastname: Kulik
authors.affiliation: Division of Hematology and Oncology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago. IL. EUA.
authors.forename: Brandon
authors.initials: B
authors.lastname: McMahon
mesh_terms: D000328:Adult; D000368:Aged; D000906:Antibodies / Q000097:blood; D000925:Anticoagulants / Q000009:adverse effects* / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D002641:Chicago; D004797:Enzyme-Linked Immunosorbent Assay / Q000706:statistics & numerical data*; D005189:False Positive Reactions; D005260:Female; D006493:Heparin / Q000009:adverse effects* / Q000276:immunology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008103:Liver Cirrhosis / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013921:Thrombocytopenia / Q000097:blood / Q000139:chemically induced* / Q000175:diagnosis* / Q000276:immunology / Q000401:mortality; D013997:Time Factors; D019564:Unnecessary Procedures / Q000706:statistics & numerical data*
chemical_list: D000906:Antibodies; D000925:Anticoagulants; D015415:Biomarkers; D006493:Heparin