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Quantiferon-TB Gold Plus

Mnemonic

QF PLUS TB

Synonym

Interferon-Gamma Release Assay for Tuberculosis - Latent Tuberculosis Infection (LTBI) - QFT & M TB - QFT-G & M. tuberculosis - QFT-TB - QFT-TB Plus - QuantiFERON Mitogen and NIL - QuantiFERON-TB Gold In Tube - QuantiFERON-TB Gold Plus & Mycobacterium Tuberculosis Antibody - QuantiFERON-TB Gold Plus – QFT - Interferon-gamma release assay

Includes

NIL, TB1 Minus NIL, TB2 minus NIL, Mitogen minus NIL, Qualitative Result

Specimen Collection Requirements

Collect

Whole blood is collected using the Quantiferon®-Plus Collection kit.  The 4 collection tubes must be at 17-25°C at the time of blood filling.  Collect 1 mL in each tube: [one NIL (Grey top), one TB1 Ag (Green top), one TB2 Ag (Yellow top), one MIT (Lavender top)].  The black mark on the side of tubes indicates 1 mL fill volume.  If using a butterfly collection device, prime tubing with a purge tube before filling the QFT tubes. Do not under or over-fill.  Immediately after filling the tubes, shake them 10 times just firmly enough to ensure that the entire inner surface of the tube has been coated with blood.  Important:  Overly vigorous shaking may cause cell disruption and can lead to aberrant results.

 

NOTE:

Collect specimens for QuantiFERON test last. Preferred order of QuantiFERON tubes is: Grey top, Green top, Yellow top, Lavender top. 

Handling

Label each tube, placing the patient label on the tube so as not to block visibility of the black line on the tube.  Keep tubes at ambient temperature (22°C ± 5°C) and transport to the laboratory as soon as possible. Due to multistep preanalytical process for this test, to ensure consistency of specimen processing, the specimens should be received by the laboratory no later than within 14 hours of collection.

Preferred Volume

Each of the 4 tubes included in the Collection kit must fill to the 1 mL mark indicated by the black line on the tube.  

Minimum Volume

1.0 mL in each of the 4 tubes

Transport

The 4 tubes must be transported at ambient temperature (22°C ± 5°C) and MUST arrive at the Central Laboratory within 16 hours of collection. 

Rejection Criteria

Refrigerated or frozen specimens, specimen tubes with incorrect volume and specimens that arrive in the laboratory more than 16 hours post collection will be rejected.

Single tube collection (lithium heparin).

Stability

Ambient (17-27°C) 16 hours post collection; Refrigerated (2-8°C) not acceptable; Frozen (<-20°C) not acceptable

Testing Information

Note

For clients authorized to incubate specimens prior to specimen submission the following stability and handling guidelines apply: Transport spun (separated plasma) specimens at refrigerated temperature (2-8°C). Separated plasma specimens should be stored at 2-8°C up to 28 days.

Performed

Monday – Saturday

Reported

3-5 days

Method

Chemiluminescent Immunoassay (CIA)

Reference Values

Reference Values

Negative

Comments

QFT Gold Plus is a qualitative diagnostic test measuring in vitro interferon gamma response to peptide antigens simulating mycobacterial proteins.  The magnitude of response cannot be correlated to stage or degree of infection, level of immune responsiveness, or likelihood for progression to active disease.  Diagnosing or excluding tuberculosis requires a combination of epidemiological, historical, medical and diagnostic findings that should be taken into account when interpreting QFT Gold Plus results.

 For detailed recommendations, refer to CDC publication Guidelines for Using Interferon Gamma Release Assays to Detect Mycobacterium Tuberculosis Infection.

CPT Codes

86480

Last Updated: Wednesday, January 27, 2021 02:35:23 AM


Client Services: 503-413-1234