Comparison of D-dimer point of care test (POCT) against current laboratory test in patients with suspected venous thromboembolism (VTE) presenting to the emergency department (ED)

Aims To compare quantitative point of care (POC) with laboratory d-dimer testing in patients with suspected venous thromboembolism (VTE) presenting to the emergency department. Methods A prospective single centre diagnostic study in adults presenting with suspected VTE (pleuritic chest pain or leg swelling) Results Main outcome measures were the statistical correlation of the two methods. Secondary outcome measures were: test turnaround times, correlation between D-dimer levels, Wells score and final diagnosis. The results showed that there was strong evidence of POC D-dimer being sufficiently accurate to be used as a screening device. The correlation between the two logged assay scores was good. Both logged scores correlated similarly with the Wells score. Once an equivalent cut-off value for POC D-dimer (412 ng/mL) was established, there were only 4 of 100 cases all of which were extremely close to the cut-off. D-dimer turnaround time decreased by 83%. A further recent analysis of laboratory times done in 2013 demonstrates that POC D-dimer results remain 62% quicker. Based on the D-dimer results 27 patients were scanned. The median Wells score in this group was 3.0 (range 2-10) median POC D-dimer levels of 2590 (412-5000) and median lab D-dimer levels of 864 (230-13 000) showing good correlation between D-dimer positive patients and the Wells score. Seven patients had positive scans. There was a significant difference in both logged D-dimer scores between the negative and positive groups indicating that raised D-dimer levels correlate well with final diagnosis. Conclusions The POC device was comparable with the laboratory device and was sufficiently accurate to be used as a screening tool in the emergency department setting.