TY  - BOOK
AU  - Chan, Chee Man
AU  - Shorr, Andrew F
AU  - Woods, Christian J
TI  - The Role for Optical Density in Heparin-Induced Thrombocytopenia: A Cohort Study
SN  - 0012-3692
PY  - 2015///
KW  - *Anticoagulants/ae [Adverse Effects]
KW  - *Enzyme-Linked Immunosorbent Assay
KW  - *Heparin/ae [Adverse Effects]
KW  - *Thrombocytopenia/ci [Chemically Induced]
KW  - *Thrombocytopenia/di [Diagnosis]
KW  - Aged
KW  - Cohort Studies
KW  - Female
KW  - Hospitalization
KW  - Humans
KW  - Male
KW  - Middle Aged
KW  - Platelet Count
KW  - ROC Curve
KW  - Sensitivity and Specificity
KW  - Thrombocytopenia/co [Complications]
KW  - MedStar Washington Hospital Center
KW  - Medicine/Pulmonary-Critical Care
KW  - Journal Article
KW  - Observational Study
KW  - Research Support, Non-U.S. Gov't
N1  - Available online from MWHC library: 1935 - present, Available in print through MWHC library: 1999 - 2006
N2  - BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a serious complication of heparin utilization. An enzyme-linked immunosorbent assay (ELISA) is usually performed to assist in the diagnosis of HIT. ELISAs tend to be sensitive but lack specificity. We sought to use a new cutoff to define a positive HIT ELISA; CONCLUSIONS: Increasing the OD threshold enhances specificity without noticeably compromising sensitivity. Altering the definition of the HIT ELISA could prevent unnecessary testing and/or treatment with non-heparin-based anticoagulants in patients with possible HIT; METHODS: We conducted a prospective observational study of hospitalized patients undergoing ELISA testing. All patients who underwent ELISA testing were eligible for inclusion (n = 496). Irrespective of the results, all subjects had confirmatory testing with a serotonin release assay (SRA). We compared a threshold optical density (OD) > 1.00 to the current definition of a positive ELISA (OD > 0.40) as a screening test for a positive SRA. We used sensitivity, specificity, and area under the receiver operating curve to determine whether an OD > 1.00 would improve diagnostic accuracy for HIT; RESULTS: The SRA was positive in 10 patients (prevalence, 2.0%). Adjusting the definition of a positive HIT ELISA to > 1.00 maintained the sensitivity and negative predictive value at 100% in the cohort. The positive predictive value of the higher cutoff OD was more than triple the positive predictive value of an OD > 0.40 (41.7% vs 13.3%). No patient with a positive SRA had an OD measurement < 1.00; TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00946400; URL: www.clinicaltrials.gov
UR  - http://dx.doi.org/10.1378/chest.14-1417
ER  -