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QuantiFeron Gold TB

Item Value
Available Stat? No
Test code QNB
Performed by Immunology
In House Availability Tuesday and Friday (day shift)
Method Enzyme Immunoassay
Collection Instructions Note: A set of three QuantiFeron Gold tubes (Gray cap/white ring, Red cap/white ring, and Purple cap/white ring) must be collected at the same time, with 1mL of blood in each tube. It is mandatory that the tubes be filled correctly as underfilled or overfilled tubes will be rejected by lab.

INPATIENT:
COLLECT SAMPLE 4 AM - 6:30 PM ON MONDAY-FRIDAY ONLY. DO NOT COLLECT SAMPLE ON WEEKENDS OR UCSF OBSERVED HOLIDAYS.

OUTPATIENTS:
COLLECT BETWEEN 7 AM – 6:30 PM ON MONDAY – FRIDAY BY UCSF LABORATORY STAFF AT OUR OUTPATIENT FACILITIES.DO NOT COLLECT SAMPLE ON WEEKENDS OR UCSF OBSERVED HOLIDAYS.

1. For Parnassus and Mission Bay inpatient only, pick up collection kits from Laboratory Central Processing. Outpatient clinics will have their own collection kits.

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 firmly and vertically for 10 times and label tubes appropriately.

4. These are time sensitive samples, please 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 tubes be filled correctly as underfilled or overfilled tubes will be rejected by lab.
Amount to Collect 3 mL blood, place 1 mL of blood into each tube in the collection kit
Sample type 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. Overfilled or underfilled tubes received.
Processing notes CENTRAL PROCESSING STAFF:
Accession the samples immediately upon receipt and send to Immunology Lab at China Basin at room temperature. Samples received after 6:30pm or 7pm, please send them with Microbiology Lab courier to China Basin Mircrobiology Lab. Please reject samples collected after 6:30pm that missed 8:30pm courier run.

Exception: Accept samples collected outside of "4am – 6:30pm Monday - Friday" from patients admitted for a kidney transplant at Parnassus only. The tubes will be delivered by kidney transplant unit staff to Central Processing Lab at Parnassus to accession. Send the samples to Microbiology Lab at China Basin for incubation and processing.

Normal range NEGATIVE
Synonyms Tuberculosis; TB; TB skin test; Interferon gamma; IFN gamma
Stability Samples need to be incubated at China Basin as soon as possible after collection (within 16 hours of collection).
Turn around times 5-7 days
Additional information Nil
(IU/mL) TB antigen - Nil (IU/mL) Mitogen - Nil
(IU/mL) QTF Result(Interpretation)


≤ 8.0 < 0.35

OR
≥ 0.35 and
< 25% of Nil value
≥0.5 Negative (M.tuberculosis infection NOT likely)
≤8.0 ≥ 0.35

and
≥ 25% of Nil value Any Positive

(M. tuberculosis infection likely)
≤8.0 < 0.35

OR
≥ 0.35 and
< 25% of Nil value
<0.5 Indeterminate

(for TB-Antigen responsiveness)
>8.0
Any
Any Indeterminate

(for TB-Antigen responsiveness)


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
LOINC code
QUANTIFERON(R)-TB GOLD 45323-3
NIL 46217-6
TB-NIL 64084-7
MITOGEN-NIL 46216-8

Last Updated 11/15/2017 12:31:29 PM
Entry Number 1804
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