Which serological test is recommended for detecting antibody in cerebrospinal fluid?

The recommended serological test for detecting antibodies in cerebrospinal fluid (CSF) is the CSF-VDRL test. This test is specifically designed to diagnose neurosyphilis, which occurs when the Treponema pallidum bacteria invade the central nervous system. The CSF-VDRL is particularly valuable because it can identify reactive antibodies within the CSF, indicating an ongoing immune response against the syphilis pathogen.

This test is preferred over serum tests because it assesses the presence of antibodies in the CSF itself, which can provide direct evidence of infection in the central nervous system. If individuals are suspected of having neurosyphilis, the demonstration of antibodies in the CSF is crucial for confirming the diagnosis, as systemic tests might not provide this localized information.

Other tests mentioned, such as RPR and VDRL (which are typically performed on serum), are less effective for diagnosing conditions involving the CNS. The MHA-TP test, while useful for syphilis diagnosis, primarily assesses for Treponema pallidum antibodies in serum rather than in CSF. Therefore, the CSF-VDRL is the test that best addresses the need for CSF evaluation in cases of suspected neurosyphilis