The CSF‐FTA test and the significance of blood contamination

Abstract

Although the fluorescent treponemal antibody absorption (FTA‐ABS) test has found wide application in the diagnosis of syphilis, the cerebrospinal fluid fluorescent treponemal antibody (CSF‐FTA) test is still controversial in the diagnosis of neurosyphilis. We found the CSF‐FTA test extremely sensitive to contamination with FTA‐ABS‐reactive blood at concentrations in CSF that could not be detected by visual inspection. Interpretation of a reactive test should be made with caution if red cells are present in CSF.