A test for cryptococcal antigen can give false-positive results.
Possible causes of a false-positive test for cryptococcal antigen:
(1) contaminant in transport vial
(2) exposure to soap or detergent
(3) contaminant in laboratory
(4) inactive pronase
(5) rheumatoid factor AND failure to pretreat (with pronase, 2-beta-mercaptoethanol, or dithiothreitol)
(6) cross reacting organism (Trichosporon, Ustilago maydis)
(7) laboratory error
