Point of Care D-Dimer Testing in the Emergency Department: A Bioequivalence Study

Abstract

BackgroundD-dimer is used widely as a diagnostic aid in low- and moderate-risk patients with suspected venous thromboembolism (VTE). While our laboratory utilizes VIDAS D-dimer analyzer (bioMérieux SA, France), our emergency department (ED) recently procured a D-dimer analyzer AQT90 FLEX (Radiometer Medical ApS, Denmark) for point of care testing (POCT) to facilitate patient management. We aimed to determine whether the time taken to receive D-dimer results using the 2 different analyzers differed significantly and to quantify the limits of agreement between the results of the 2 methods measured on the same patient.MethodsAdult patients presenting to the ED and requiring diagnostic workup for suspected VTE were included in this prospective observational study. Patients underwent simultaneous D-dimer measurements using the 2 different analyzers.ResultsThe paired results from 104 patients were analyzed. The median time for the D-dimer results from triage by VIDAS was 258 min (Inter-quartile range [IQR], 173-360) and by POCT was 146 min (IQR, 55-280.5); the median time difference was 101.5 min (IQR, 82-125.5). On an average, POCT D-dimer values were 15% lower on the same sample (limits of agreement, 34-213%). POCT predicted 83% of VIDAS positive results (sensitivity, 83.3% [95% confidence interval (CI), 70.4-91.3%]; specificity, 100% [95% CI, 93.6-100%]). All patients with positive imaging were identified correctly by both methods.ConclusionsPOCT delivers D-dimer results in significantly shorter turnaround times than pathology services; however, poor bioequivalence between VIDAS and POCT raises the issue of acceptability for use in the ED.

Evaluation of the usefulness of a D dimer test in combination with clinical pretest probability score in the prediction and exclusion of Venous Thromboembolism by medical residents

“…New immunological techniques such as immunoturbidimetry have gained attention because of their high sensitivity (around 98%) with intermediate specificity (better than ELISA) and short process time [ 12 ]. The introduction of Point of Care Testing helped further decrease turnaround time; however, poor bioequivalence hampered its use in clinical settings [ 13 ]. Both the PTP scoring system and DD assay has resulted in better decision-making and early thrombosis diagnosis [ 1 , 14 ].…”

D-dimer testing for safe exclusion and risk stratification in patients with acute pulmonary embolism in primary care

“…DD is a fibrin degradation product formed by the breakdown of fibrin in vivo by specific enzymes, and widely used as a diagnostic tool in low- and moderate-risk patients with suspected venous thromboembolism. [ 24 ] The study shows that the levels of DD and PT in APE patients were significantly tighter than those in controls. By comparing the AUROC, we found that the DD has higher identified diagnosis values compared with PT.…”

Point of care testing in family practice: common myths debunked

“…However these required further development and clinical evaluation of their implementation in daily practice. [36][37][38] It is possible that more patients are being tested with POCT than before, with lab-based D-dimer tests, and this may increase the number of false positives, exposing more people to the harms of CT-associated radiation.…”