Limited Utility of a Rapid Quantitative Enzyme-Linked Fluorescent Assay for the D-Dimer in the Diagnosis of Overt Disseminated Intravascular Coagulation

The role of quantitative D-dimer assay in screening for and diagnosing overt disseminated intravascular coagulation (DIC), conventionally diagnosed by the International Society of Thrombosis and Haemostasis' (ISTH) score, was evaluated. Of patients with clinical conditions associated with overt DIC, 142 with ISTH scores >= 5 (compatible with overt DIC) and 61 with ISTH scores <5 (suggestive of nonovert DIC) underwent the quantitative D-dimer assay. Accuracy indices, receiver operating characteristic (ROC) curve-derived cutoffs, and areas under curve were compared. Mean D-dimer level in overt DIC was 4147.2 +/- 2707 ng/mL. In nonovert DIC, it was 1678.9 +/- 1888.3 ng/mL. Both were higher than healthy controls (229.6 +/- 129.9 ng/mL). An optimized cutoff (2040 ng/mL) had relatively low sensitivity (75.4%) and specificity (73.8%). Extensive overlap between groups at this cutoff reduced diagnostic utility. Lowered cutoffs increased sensitivity (eg, 91.5% at 1000 ng/mL) but diminished specificity (59%), limiting use of screening. In conclusion, the quantitative D-dimer as a stand-alone assay has a limited role in diagnosis of overt DIC.