False positive serology in cerebrospinal fluid associated with a spinal cord tumor.

Biologic false positive serology in cerebrospinal fluid has been reported as exceedingly rare. In a patient with a spinal cord tumor and elevated cerebrospinal fluid protein, the cerebrospinal fluid was reactive to VDRL and fluorescent treponemal antibody absorption (fta-abs) tests, but became nonreactive with removal of the tumor. This biologic false positive reaction may be related to the elevated cerebrospinal fluid protein, as similar false positive reactions have occurred in blood with abnormal or elevated proteins. Cerebrospinal fluid reactive to the VDRL and FTA-ABS tests does not always indicate neurosyphilis.