The VIDAS D-dimer test for venous thromboembolism: a prospective surveillance study shows maintenance of sensitivity and specificity when used in normal clinical practice
Received 26 June 2006; received in revised form 18 September 2006; accepted 25 September 2006.
Abstract
Background
As a result of a number of clinical management studies, D-dimer (DD) tests such as VIDAS (BioMérieux Australia P/L-Sydney, NSW) have been recommended to reduce venous thromboembolism (VTE) investigations. Surveillance studies for new tests are recommended. We prospectively assessed VIDAS DD in normal practice.
Methods
Consecutive emergency patients and inpatients (IPs) with DD or VTE investigations were prospectively identified. Investigation results and early chart review including predefined factors reducing specificity were documented. A latex DD was also performed. Patients were followed for at least 3 months for recurrent VTE.
Results
Four hundred three patients (emergency, 64%; VTE-positive, 12%; 95% followed up) were analyzed. VIDAS sensitivity was 96% (95% confidence interval 86%-99%), specificity 38% (confidence interval, 34%-44%; negative likelihood ratio, 0.11), and emergency specificity 51%. Latex sensitivity was 76%. Cancer, trauma, recent operations, IP status, and advanced age were associated with markedly reduced specificity. Specificity in older emergency patients (>70 years old) and younger IPs (<70) without comorbidities was 20% to 30%, but sensitivity was maintained at 100%.
Conclusions
VIDAS DD probably maintains adequate sensitivity in normal clinical practice for low- or even intermediate-risk patients. Latex agglutination had poor sensitivity. Specificity is best in younger low-morbidity emergency patients. These findings need validation in larger multicenter surveillance studies.
Department of Emergency Medicine, Sir Charles Gairdner Hospital, Perth, Australia
Department of Academic Emergency Medicine, University of Western Australia, Perth, Australia
Department of Emergency Medicine, Royal Perth Hospital, Perth, Australia
Corresponding author. Department of Emergency Medicine, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, Perth WA, Australia 6009. Tel.: +61 8 93463333; fax: +61 8 93463516.
Data in this study have been presented as: Mountain D, Haig A. Presentation. A prospective observational study in an unselected population of the VIDAS D-dimer (VIDAS DD) test for excluding acute venous thrombo-embolic (VTE) disease shows retention of sensitivity and specificity in a real environment. ACEM/ASEM joint scientific meeting, November 2000, Canberra, Australia.
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