CPT® Code 85598

The CPT® Code 85598 refers to a specific laboratory test known as the hexagonal phospholipid neutralization assay, which is utilized to detect the presence of lupus anticoagulants (LAs) in the blood. Lupus anticoagulants are a diverse group of antibodies that target phospholipid-protein complexes, leading to an increased clotting time in affected individuals. The assay operates on the principle that when a hexagonal phospholipid source is introduced to a sample containing LAs, these antibodies are neutralized, resulting in a shortened clotting time. This test employs a two-part activated partial thromboplastin time (aPTT)-based methodology, comparing the clotting times of samples tested with and without hexagonal phase phosphatidyl-ethanolamine (HPE) using a reagent sensitive to LAs. A significant difference in clotting times—specifically, if the clotting time without HPE exceeds that with HPE by 8 seconds or more—indicates a positive result for the presence of lupus anticoagulants. While a positive result may suggest systemic lupus erythematosus (SLE), it is important to note that many individuals with positive results do not have this condition. The test is particularly relevant for patients with a history of spontaneous abortion, thrombosis, or infections, as the ongoing presence of LAs in plasma is associated with an elevated risk of these complications, especially concerning arterial and venous thrombosis.