Diagnostic Accuracy of a New d-Dimer Assay (Sclavo Auto d-Dimer) for Exclusion of Deep Vein Thrombosis in Symptomatic Outpatients. (April 2017)

• Record Type: Journal Article
• Authors: Legnani, Cristina; Cini, Michela; Frascaro, Mirella; Rodorigo, Giuseppina; Sartori, Michelangelo; Cosmi, Benilde
• Is Part Of: Clinical and applied thrombosis/hemostasis. Volume 23:Number 3(2017)
• Page Start: 221
• Page End: 228
• Publication Date: 2017-04
• Subjects: d-dimer -- pulmonary embolism -- deep vein thrombosis; Hemostasis -- Periodicals; Thrombosis -- Periodicals; 616.13
• DOI: 10.1177/1076029616649436
• Languages: English
• ISSNs: 1076-0296

Abstract

In patients presenting non-high clinical pretest probability (PTP), a negatived -dimer can exclude venous thromboembolism without imaging tests. However, eachd -dimer assay should be validated in prospective studies. We evaluated an automatedd -dimer immunoassay using the Sclavo Autod -dimer (Sclavo Diagnostics Int, Sovicille, Italy) provided by Dasit Diagnostica (Cornaredo, Milan, Italy). Three hundred two consecutive outpatients suspected of leg deep vein thrombosis (DVT) with non-high PTP were included. The Sclavo Autod -dimer assay was evaluated on 2 analyzers (Sysmex CA-7000 and Sysmex CS-2100; Sysmex Corporation, Kobe, Japan, provided by Dasit). The cutoff value (200 ng/mL) was established a priori. Prevalence of DVT was 11.9%. Since no false-negative patients were detected, the sensitivity and negative predictive values (NPVs) were 100% (sensitivity = CA-7000: 100% [95% confidence interval, CI: 93.3-100], CS-2100: 100% [95% CI: 93.3-100]; NPV = CA-7000: 100% [95% CI: 97.9-100], CS-2100: 100% [95% CI: 98.0-100]). Specificity was 65.4% (95% CI: 59.4-71.1) and 69.2% (95% CI: 63.3-74.7) for CA-7000 and CS-2100, respectively. Specificity increased when a higher cutoff value (234 ng/mL) was used for patients aged ≥60 years without compromising the safety. Assay reproducibility was satisfactory at concentrations near the cutoff value (total coefficient of variations <10%). In conclusion, the Sclavo Autod -dimer assay was accurate when used for DVT diagnostic workup in outpatients with non-high PTP. Based on its high sensitivity and NPV, it can be used as a stand-alone test in outpatients with non-high PTP. Given its high specificity, the number of patients in whom further imaging techniques can be avoided increased, improving the yield of the test.