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QuantiFERON Gold TB

Item Value
Approval req'd? Yes, inpatients, except liver and kidney transplant service, require approval by ID service
Available Stat? No
Test code QNTFP
Performed by Quest
Sendout? Yes
Method ELISA
Collection Instructions Note it is mandatory the the tubes be filled correctly as underfilled or overfilled tubes will be rejected by Quest.

Samples are not collected by UCSF laboratory staff or at our outpatient facilities. Patients must be referred to a Quest patient service center (LabCorp for Brown & Toland patients) for sample collection and testing.

Click here to locate Quest Outpatient service locations

Click here to locate LabCorp outpatient service centers

1. Pick up collection kits from Laboratory Central Processing .
2. Collect 1 ml of blood by venipuncture directly into each of the three tubes (Nil, TB Antigen, Mitogen). Fill each tube up to the black mark. Under or overfilling of the tubes may lead to erroneous results.
3. Mix the tubes by shaking vigorously for 5 seconds and label tubes appropriately.
4. Deliver the tubes to the Laboratory Central Processing immediately.
Container type Requires special collection kit available from central laboratory containing:

QFT-Nil Control tube Gray cap, white ring
QFT-TB Antigen tube Red cap, white ring
QFT-Mitogen Control tube Purple cap, white ring

Note it is mandatory the the tubes be filled correctly as underfilled or overfilled tubes will be rejected by Quest.
Amount to Collect 3 mL blood, place 1 mL of blood into each tube in the collection kit
Sample type Whole blood
Preferred volume 3 mL blood, place 1 mL of blood into each tube in the collection kit
Min. Volume 3 mL blood, place 1 mL of blood into each tube in the collection kit
UCSF Rejection Criteria Frozen samples. Improperly collected samples.
Accession the samples immediately upon receipt and hand carry to Microbiology.

1. Re-shake tubes immediately prior to incubation.
2. Incubate the 3 tubes in the 36-38C heat block.for a minimum of 16 hours (no more than 24 hours).
3. Contact ID Service for approval, except if liver or kidney transplant service. If test is not approved by ID, ask Central Processing supervisor to credit the test.
4. On the next day after incubation is completed, centrifuge each of the 3 tubes for 15 mins.
5. Place the tubes in the Central Processing refrigerator designated for samples to be sent out, in the rack inside the tray labeled Send-outs.
Ref Lab Rejection Criteria Overfilled or underfilled tubes received.
Normal range Not detected
Synonyms Tuberculosis; TB; TB skin test; Interferon gamma; IFN gamma
Uncentrifuged 72 hours at room temperature
Centrifuged 28 days refrigerated
Turn around times 5-7 days
Additional information The QuantiFERON test detects the release of IFN-gamma released by whole blood lymphocytes after incubation with tuberculin purified protein derivative and phytohemagglutinin.

The test is intended for screening asymptomatic individuals who may be at risk for latent tuberculosis (recent immigrants, prisoners and prison/jail employees) or TB exposure (military, hospital personnel). In these settings it is equivalent but no better than skin testing.

QuanitFERON testing may be more specific than skin testing when screening individuals with a history of prior BCG vaccination.

It is NOT recommended for use in patients with symptoms of active TB (known to cause decreased IFN-G responses), contacts of patients with active TB, immunosuppressed patients, patients with diabetes, silicosis, chronic renal failure, leukemia, lymphoma, head/neck cancer, lung cancer, s/p gastrectomy or jejunoileal bypass. In these situations skin testing is recommended.
CPT coding 86480-90
Last Updated 12/21/2015 8:59:15 AM
Entry Number 1061
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