Dilute Russell's Viper Venom Time (DRVVT) Mix Ratio, Plasma

Casandra

Casandra Test Code MC66678Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID DRVI2CPT Code 85613

Dilute Russell's Viper Venom Time (DRVVT) Mix Ratio, Plasma

Clinical Use

Use

This test is useful for detecting the presence or helping to exclude the presence of lupus anticoagulants (LA). It identifies LA that do not prolong the activated partial thromboplastin time (APTT) and evaluates unexplained prolongation of the APTT or prothrombin time clotting tests. Additionally, it helps distinguish LA from a specific coagulation factor inhibitor or coagulation factor deficiencies. The test uses the dilute Russell's viper venom time (DRVVT) mix assay to measure clotting time, aiding in the diagnosis or exclusion of LA.

Special Instructions

The test is not orderable as a standalone and is only available as part of a reflex testing panel. It involves the mixing of patient plasma with normal pooled plasma and freeze submission of platelet-poor plasma within specific temperature conditions. Ensure plasma is centrifuged, and follow coagulation handling guidelines closely to avoid false results.

Limitations

The test has a sensitivity of approximately 65% to 70% for detecting lupus anticoagulants (LA), with a specificity of 95% or higher. There is potential for false positives in patients on anticoagulants. Residual platelets in frozen plasma can lead to reduced sensitivity and specificity, potentially causing false negatives. The test might not detect all LA, and some LA may only be detectable by other tests.

Test Details

FDA Approved