CPT® Code 85335

The CPT® Code 85335 refers to a laboratory test known as the factor inhibitor test. This test is specifically designed to measure the activity of factor inhibitors, which are IgG antibodies that can develop against clotting factors in the blood. The presence of these inhibitors can significantly impact the effectiveness of clotting factor concentrates, leading to complications such as treatment failure, bleeding episodes, and potentially life-threatening hemorrhages. Factor inhibitors are most commonly observed in patients suffering from hemophilia A, which is associated with a deficiency in factor VIII, and hemophilia B, linked to a deficiency in factor IX. These patients often receive clotting factor concentrates as part of their treatment regimen for their hemolytic disorders. However, it is important to note that inhibitor factor antibodies can also arise in other populations, including elderly individuals without a prior history of hemophilia, postpartum women, and patients with various autoimmune disorders. The test itself involves obtaining a blood sample through a venipuncture, which is reported separately, and the analysis is conducted on platelet-poor plasma using a clot-based assay to accurately assess the inhibitor activity.