The Role for Optical Density in Heparin-Induced Thrombocytopenia: A Cohort Study.
Citation: Chest. 148(1):55-61, 2015 Jul.PMID: 25611568Institution: MedStar Washington Hospital CenterDepartment: Medicine/Pulmonary-Critical CareForm of publication: Journal ArticleMedline article type(s): Journal Article | Observational Study | Research Support, Non-U.S. Gov'tSubject headings: *Anticoagulants/ae [Adverse Effects] | *Enzyme-Linked Immunosorbent Assay | *Heparin/ae [Adverse Effects] | *Thrombocytopenia/ci [Chemically Induced] | *Thrombocytopenia/di [Diagnosis] | Aged | Cohort Studies | Female | Hospitalization | Humans | Male | Middle Aged | Platelet Count | ROC Curve | Sensitivity and Specificity | Thrombocytopenia/co [Complications]Year: 2015Local holdings: Available online from MWHC library: 1935 - present, Available in print through MWHC library: 1999 - 2006ISSN:- 0012-3692
Item type | Current library | Collection | Call number | Status | Date due | Barcode |
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Journal Article | MedStar Authors Catalog | Article | 25611568 | Available | 25611568 |
Available online from MWHC library: 1935 - present, Available in print through MWHC library: 1999 - 2006
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.
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