Cryptococcal Antigen

CERNER / EPIC MNEMONIC:

CRYPTO AG (for CSF), BL CRYPTO (for blood)

POE DESCRIPTION: CRYPTOCOCCAL ANTIGEN; CRYPTO AG
CPT CODE:

87327

TEST INFORMATION:

The test is a Lateral Flow Assay which is an immunochromatographic test system  for the detection of Cryptococcal antigen.  This test replaces India Ink preparation for cerebrospinal fluid specimens.

DAYS PERFORMED: CSF: daily, 24 hours, performed STAT; blood: Monday-Friday, 0800-1430
TURNAROUND TIME: STAT, 2 hours after receipt of the specimen in the laboratory; routine, same day if received by 1330. Titer: 1-3 days.
CONTAINER TYPE:

Sealed sterile container for CSF, red top Vacutainer® tube for blood

SPECIMEN REQUIREMENTS: Cerebrospinal fluid, blood (serum)
REJECTION CRITERIA: Insufficient quantity of specimen, inappropriate specimen container, hemolyzed blood specimen, bloody cerebrospinal fluid specimen.
MINIMUM VOLUME: 1 mL CSF, 5 mL blood (1 mL serum)
HANDLING INSTRUCTIONS: Specimen should be transported as soon as possible. When transportation is delayed, leave at room temperature.
REFERENCE RANGE: No cryptococcal antigen detected
LIMITATIONS OF TEST: False negative results may occur due to a low concentration of the polysaccharide antigen or due to a prozone effect at high antigen concentrations. False positive results may occur due to invasive infections with the yeast Trichosporon beigelii,  Capnocytophaga species, or Rothia (Stomatococcus) mucilaginosus.
METHODOLOGY:

Lateral Flow Assay

ADDITIONAL INFORMATION: A titer will be reported for all positive results. A higher titer usually corresponds with worse disease. Pretreatment of blood specimens with pronase reduces false-positives and increases the sensitivity of the method. A fungal culture should also be performed for patients who are suspected of having cryptococcosis. Antigen detection may precede the detection of viable organisms in cerebrospinal fluid Gram stains and fungal culture. The India Ink preparation has been replaced by the cryptococcal antigen procedure due to the increased sensitivity. A cryptococcal antigen will routinely be performed on all cerebrospinal fluid specimens submitted for a fungal culture providing an adequate volume of specimen is submitted.
LAST UPDATED:

12-17-2013