CPT® Code 85613

The CPT® Code 85613 refers to the Russell viper venom time (RVVT) test, specifically the diluted version of this test. This procedure involves obtaining a blood sample from the patient, which is then analyzed to measure the RVVT. The primary purpose of this test is to detect the presence of lupus anticoagulants in the plasma. Lupus anticoagulants are a type of nonspecific clotting inhibitor that can interfere with the normal clotting process, potentially leading to increased risk of thrombosis. In contrast to the undiluted RVVT test, which is coded under CPT® Code 85612, the diluted RVVT (dRVVT) utilizes a low phospholipid reagent that consists of Russell viper venom combined with excess calcium. This dilution is crucial as it lowers the phospholipid concentration, thereby enhancing the sensitivity of the test for identifying lupus anticoagulants. The measurement of clotting time is performed using a photo-optical method, which provides an accurate assessment of the coagulation status of the patient’s plasma in relation to the presence of these inhibitors.