Whole-blood immunoassay (SimpliRED) versus plasma immunoassay (NycoCard) for the diagnosis of clinically suspected deep vein thrombosis.

BACKGROUND

The level of D-dimer in the blood reflects the level of lysed, cross-linked fibrin, and is a useful diagnostic marker in patients with clinically suspected deep vein thrombosis (DVT). In this study, two assays for the measurement of D-dimer levels were compared: the new, whole-blood immunoassay, SimpliRED, which can be performed at the patient's bedside in two minutes; and the plasma immunoassay, NycoCard.

PATIENTS AND METHODS

D-dimer levels were determined using these two techniques in 108 patients with clinically suspected DVT. To ascertain or rule out the diagnosis of DVT compression ultrasonography using a colour coded Duplex instrument was done. 8 doubtful cases were diagnosed by ascending phlebography. By these procedures DVT was confirmed in 33 patients and ruled out in the remaining 75 cases.

RESULTS

The SimpliRED assay exhibited a sensitivity of 1.0 (CI 0.89-1.0) and a specificity of 0.75 (CI 0.63-0.84); negative predictive value 1.0 (CI 0.94-1.0), positive predictive value 0.63 (CI 0.49-1.0). By contrast, the NycoCard assay displayed a sensitivity of 0.85 (CI 0.68-0.95) and a specificity of 0.65 (CI 0.53-0.76); negative predictive value 0.91 (CI 0.80-0.97), positive predictive value of 0.52 (CI 0.38-0.66).

CONCLUSION

The results show that the SimpliRED assay is a valuable tool in the diagnosis of clinically suspected DVT, especially when laboratory facilities are not accessible.