QuantiFERON®-TB Gold Plus
Also known as: Interferon-gamma Release Assay (IGRA) for Mycobacterium tuberculosis, QFT-Plus
Use
QuantiFERON-TB Gold Plus is an in vitro diagnostic test using a peptide cocktail of CD4+ and CD8+ T cell antigens to stimulate cells in heparinized whole blood. Detection of interferon-gamma by enzyme-linked immunosorbent assay (ELISA) is used to identify in vitro responses to these peptide antigens that are associated with Mycobacterium tuberculosis infection. QuantiFERON-TB 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 diagnostic evaluations.
Special Instructions
QuantiFERON is time-sensitive and specimens must be received in the laboratory within 14 hours of collection. Specimen collection times vary based on logistics from the blood draw location to a Labcorp lab. This test requires a special collection kit that may not be available at all PSCs. For client-incubated submissions, order QuantiFERON®-TB Gold Plus (Client Incubated) (Test No. 182893).
Limitations
A negative QFT-Plus result does not eliminate the possibility of M. tuberculosis infection or disease. False negatives may result from the infection stage, co-morbid conditions affecting immune function, improper blood collection and handling, or test execution errors. Heterophile antibodies or non-specific IFN-gamma responses may interfere with specific detection. Positive results should not solely define infection status and require further medical investigation for active tuberculosis.
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 71773-6
- 8251-1
- 71773-6
- 64084-7
- 88517-8
- 71776-9
- 71774-4
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
1 mL x four tubes
Minimum Volume
1 mL x four tubes
Container
QuantiFERON®-TB Gold Plus kit
Collection Instructions
Blood collection tubes should be at room temperature at the time of collection. Use a needle and holder (not a butterfly) unless necessary. Fill tubes to the black fill line, shake tubes 10 times, label, and return to the 'QFT kit' box. Keep at room temp, send to lab within 14 hours.
Storage Instructions
Maintain specimen at room temperature. Incubate within 16 hours of collection.
Causes for Rejection
Grossly hemolyzed, icteric, or lipemic samples; expired collection tubes; centrifuged, refrigerated, or frozen specimens; specimens more than 14 hours old; receipt of only three tube collection kit; under-filled or over-filled tubes; tubes that do not yield sufficient plasma.