TB Interferon gamma release assay (IGRA)

Pathology category

Microbiology - Virology

Code

TBQF

Referral code

Request form

ICE request form. Request form should include relevant clinical details and should only be performed in the following situations: 1. To screen a patient in contact with cases of active TB2. To screen patients undergoing or about to undergo immunosuppressive therapy3. To screen health care workers via occupational health

Test information

The test should only be used to test for latent TB; if active TB is suspected samples from the likely site of TB infection should be collected. Please refer to PHE and NICE guidelines for more information and if you are unsure whether a sample needs to be taken, please speak to an infectious disease physician or a consultant microbiologist. Tests performed in a UKAS Accredited Medical Laboratory No. 8873.

Guidelines

Tuberculosis (TB): diagnosis, screening, management and data

Pre-analytical

The sample once taken MUST be delivered to the lab within 16 hours; samples arriving after this time will not be processed. Samples should be kept at room temperature. Please do NOT refrigerate. Please allow extra time for transport between sites.

Reference range

Tube type

Tube type info

2 x lithium heparin green topped tubes

Special requirements

Samples must be received in the Worcester Microbiology laboratory between 09:00-17:00 Monday- Thursday.

Minimum volume

2 X 4ml full. Please note samples will be rejected if insufficient sample is sent

Assay frequency

Monday – Friday

TAT Inpatient (urgent)

72 hours

TAT Inpatient

72 hours

TAT GP/Outpatient

72 hours

Referral lab