Cryptococcal Antigen

Description: 
Serum and/or cerebrospinal fluid (CSF) test for Cryptococcal Antigen. This test should only be requested when clinical evidence suggests the diagnosis of Cryptococcal disease. This rapid test can be particularly useful in investigating cases of meningitis in the immunocompromised. Turn around time results are available within 4 hours of receipt of sample.
Clinical details: 
Cryptococcosis is caused by the encapsulated yeast Crytococcus neoformans. Cryptococcal infections most commonly occur in immunocompromised individuals. Meningo-encephalitis is the commonest manifestation but other sites can be affected.
Synonyms or keywords: 
CRAG, crypto, Cryptococcus neoformans, Cryptococcus gattii
Sample type and Volume required: 
6-8 ml Clotted blood yellow top tubes, CSF plain universal (1ml). This test cannot be performed on haemolysed serum.
Call in advance: 
Bleep out of hours (17.00-9.00) on bleep number 1802
Turnaround time: 
4 hours of receipt of sample. Positive results are telephoned to the ward or clinical team by Microbiology Clinical staff.
Special sample instructions: 

Use of sterile technique for performing lumbar puncture and decanting sample into sterile universal containers. Ensure sufficient CSF is collected for the tests requested. If in doubt, contact the medical microbiologist.

Storage and transport: 
Please place labelled samples in a sealed transport bag and send to Central Specimen Reception (CSR). Samples should be refrigerated if transport to the laboratory is delayed.
Contacts:
Infection Sciences Department at St Thomas' Hospital
020 7188 8008
St Thomas' Hospital
North Wing - 5th Floor
Westminster Bridge Road
London SE1 7EH
Core opening hours: Monday-Friday 0900-1730


For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 27/11/2017