Return to Test Directory
Quantiferon-TB Gold Plus (8000101014)
Test Mnemonic:

QUANTIFERON-TB ASSAY
Specimen Requirements:

 

 

 
Collection:

Collect  5 mL of whole blood into a 6 mL blood collection tube containing Lithium-Heparin as the anticoagulant.   

 
Container:

Lithium Heparin tube (dark green cap)  
Minimum Volume:

5 mL
Storage/Transport:

Transport to the laboratory refrigerated or on ice. 
Specimen Preparation:

Collect whole blood directly into a Lithium-Heparin blood collection tube (minimum volume 5 mL) and gently mix by inverting the tube several times to dissolve the heparin.

Collect by venipuncture only - DO NOT collect via line. 

Important:  Lithium-Heparin tube should be at room temperature (17-25 degrees Centigrade) at the time of blood collection.

Blood drawn into Lithium-Heparin tube must be held at room temperature (17-25 degrees Centigrade) for 15 minutes.  Transport to the laboratory refrigerated (2-8 degrees Centigrade) or on ice.
Stability:

Lithium-Heparin tube must not remain at room temperature for more than 3 hours after collection.  Refrigerate or send to the lab on ice. 

Refrigerated specimen must be received into the laboratory within 48 hours from time of collection.
Causes for Rejection:

Underfilled Lithium-Heparin tube (below 5 mL). Refrigerated Lithium-Heparin tube received in lab after 48 hours from the time of collection.  Lithium-Heparin tube not refrigerated within 3 hours of collection. Specimen container unlabeled or labeled incorrectly. No date/time of collection or collector completed.
Reference Range:

 

Components Reference Interval
QuantiFERON-TB Gold In-Tube Negative
QuantiFERON-TB1 minus NIL 0.34 IU/mL or less
QuantiFERON-TB2 minus NIL 0.34 IU/mL or less
QuantiFERON MITOGEN minus NIL No reference interval
QuantiFERON NIL No reference interval

 
Turnaround Time:

3 - 5 days
Methodology:

Interferon gamma release assay (ELISA)
Performed:

Clinical Microbiology Laboratory
Synonyms:

QFT, QFT Plus
Clinical Indication:

QFT Gold Plus is an indirect test for M. tuberculosis infection (including disease) and is intended for use in conjunction with risk assessment, radiography, and other medical and diagnositic evaluations.
CPT 4 Code:

86480
Note:

Test results are calculated in accordance with an FDA-approved algorithm run on QuantiFERON(R) software.


The QuantiFERON(R) TB Gold Plus (in Tube) assay is intended for use as an aid in diagnosis of TB infection. Negative results suggest that there is not TB infection. In patients with high suspicion of exposure, a negative test should be repeated. A positive test indicates infection with Mycobacterium tuberculosis. Among individuals without tuberculosis infection, a positive test may be due to exposure to M. kansasii, M. szulgai, or M. marinum. As with any screening test, positive results must be interpreted with caution and in context with associated risk factors. Diagnosing or excluding tuberculosis disease and assessing the probability of latent TB infection requires a combination of epidemiological, historical, medical and diagnostic findings that should be taken into account when interpreting QuantiFERON(R) TB results.

Strict adherence to the proper collection and processing of QFT specimen tubes is essential in obtaining proper stimulation of cells for the production of interferon gamma. The performance of the USA format of the QFT-Plus test has not been extensively evaluated with specimens from the following groups of individuals:
 

  • Individuals who have impaired or altered immune functions, such as those who have HIV infection or AIDS, those who have received transplantation managed with immunosuppresive treatment or others who receive immunosuppresive drugs (e.g., corticosteroids, methotrexate, azathioprine, cancer chemotherapy), those who have hematological disorders (e.g., leukemia and lymphomas), or those with other specific malignancies (e.g., carcinoma of the head or neck and lung)
  • Individuals younger than age 17 years
  • Pregnant women

For further information, refer to

 
When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient. Components of the organ or disease panels may be ordered individually. The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-10 code or its verbal equivalent.
Return to Test Directory