CPT® Code 86705

The CPT® Code 86705 refers to the testing of a blood sample for the presence of the hepatitis B core antibody (HBcAb), specifically the IgM antibody. Hepatitis B is a viral infection that leads to inflammation of the liver, caused by the hepatitis B virus (HBV). This infection can manifest in two primary phases: acute and chronic. The core antibody, HBcAb, is produced by the immune system during and after an acute HBV infection. It is important to note that this antibody can be present even in individuals who have successfully cleared the virus without developing a chronic infection. Additionally, HBcAb may also be detected during the chronic phase of the infection. The distinction between the tests for HBcAb is crucial. For instance, CPT® Code 86704 tests for total HBcAb using a chemiluminescent assay, which identifies both IgG and IgM antibodies in a single test without differentiating between the two. This means that while the test can indicate the presence of HBcAb, it does not specify whether the infection is acute or chronic. In contrast, CPT® Code 86705 is specifically designed to test for the IgM antibody to HBcAb, making it a valuable tool for diagnosing an acute hepatitis B infection. The presence of IgM indicates that the infection is in its initial phase, providing critical information for clinical decision-making and patient management.