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QuantiFERON®-TB Gold

Test Code


CPT Code(s)


Preferred Specimen(s)

1 mL whole blood collected in each of the following tubes: QFT-Nil control (gray cap, white or gold ring) tube; QFT-TB antigen (red cap, white or gold ring) tube; QFT-Mitogen control (purple cap, white or gold ring) tube

Minimum Volume

1 mL in each tube

Collection Instructions

1. For each patient, collect 1 mL of blood by venipuncture directly into each of three unique QuantiFERON®-TB Gold IT blood collection tubes. Tubes must be at room temperature prior to collection. Under or overfilling of the tubes may lead to erroneous results.

2. Shake them ten times just firmly enough to ensure the entire surface of the tube is coated with blood, to solubilize antigens on tube walls.

3. Transport specimen at room temperature to the laboratory immediately or within 16 hours.

Note: Specimen collection locations > 3350 feet above sea level should use the QuantiFERON® collection kit designed for "high altitude" (tubes with a gold ring on tube top).

Transport Container

QFT-Nil control (gray cap, white or gold ring) tube; QFT-TB antigen (red cap, white or gold ring) tube; QFT-Mitogen control (purple cap, white or gold ring) tube

Transport Temperature

Transport specimen at room temperature to the laboratory immediately or within 16 hours.
Special sample collection and transportation arrangements must be made prior to ordering the test. Please contact your local Quest Diagnostics customer service department for specific instructions.

Specimen Stability

Specimens should be tested as soon as possible
Room temperature: 16 hours
Refrigerated: Unacceptable
Frozen: Unacceptable

Reject Criteria

Received >16 hours old unless pre-incubated • Received refrigerated or frozen • Specimens not collected in Quantiferon®-TB Gold IT blood collection tubes


Bio Assay with IFN-Gamma Detection by Immunoassay

Performing Laboratory

Quest Diagnostics-Seattle
1737 Airport Way S Suite 200
Seattle, WA 98134-1636

Setup Schedule

Set up: No draw time restrictions for non-incubated quantiferons collected in alaska and oregon. Seattle lab will accept non-incubated quantiferons collected after 10am if a client or psc does not have an incubator; Otherwise, no draw time restrictions for non-incubated quantiferons collected in washington to include all psc's in tacoma and seamar(First Shift)

Reference Range(s)

QuantiFERON®-TB Gold Negative
NIL See Laboratory Report
Mitogen-NIL See Laboratory Report
TB-NIL See Laboratory Report

Clinical Significance

tuberculosis is a communicable disease caused by infection with M. tuberculosis complex. Infection results in either acute disease or Latent TB Infection (LTBI), a non-communicable asymptomatic condition. The main purpose of diagnosing the latent stage is to consider medical treatment for preventing overt disease. Until recently, the tuberculin skin test was the only available method for diagnosing LTBI. QuantiFERON®-TB gold eliminates false positive skin test due to BCG vaccination and most Non-Tuberculous Mycobacteria (NTM) and is an objective, reproducible qualitative test. There are no side effects or adverse reactions due to patient hypersensitivity, and no "booster effect", whereby the first test induces a false positive response on re-testing. There is no need for follow-up patient visits to obtain test results.

LOINC®' Code(s)

The Result and LOINC information listed below should not be used for electronic interface maintenance with Quest Diagnostics. Please contact the Quest Diagnostics Connectivity Help Desk for more information at 800-697-9302.

NOTE: The codes listed in the table below are not orderable Test Codes.

Result NameLOINC CodeComponent Name
40023700QUANTIFERON(R)-TB GOLD45323-3Mycobacterium tuberculosis tuberculin stimulated gamma interferon
40023710NIL46217-6Mycobacterium tuberculosis stimulated gamma interferon
40023720TB-NIL64084-7Mycobacterium tuberculosis stimulated gamma interferon^^corrected for background
40023730MITOGEN-NIL46216-8Mycobacterium tuberculosis tuberculin stimulated gamma interferon/Mitogen stimulated gamma interferon

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

LOINC assignment is based on a combination of test attributes, including the method used by the performing laboratory. For tests not performed by Quest Diagnostics, codes are assigned by the performing laboratory.

* The tests listed by specialist are a select group of tests offered. For a complete list of Quest Diagnostics tests, please refer to our Directory of Services.