CPT® Code 86788

The CPT® Code 86788 refers to the laboratory test that detects the presence of immunoglobulin M (IgM) antibodies specific to the West Nile virus. This test is crucial for diagnosing recent infections with the West Nile virus, particularly in patients exhibiting symptoms consistent with viral infection. The IgM antibodies are typically present in the blood serum or cerebrospinal fluid (CSF) of individuals who have been infected with the virus, and their detection is a key indicator of an active or recent infection. The testing process involves collecting samples of blood serum or CSF, ideally between 8 to 21 days after the onset of symptoms, to ensure accurate results. For confirmation of the diagnosis, serum samples are often tested at least two weeks apart, during both the acute and convalescent phases of the illness. The most reliable method for detecting IgM antibodies in CSF is through the MAC-ELISA (IgM antibody capture enzyme-linked immunosorbent assay) technique, as the presence of IgM in CSF indicates that the antibodies have crossed the blood-brain barrier, confirming a central nervous system infection. Additionally, plaque-reduction neutralizing tests can be performed on paired serum or CSF samples taken at least two weeks apart, with a four-fold increase in antibody titer serving as further confirmation of West Nile virus infection.