QuantiFERON®‑TB Gold Plus, 4 Tubes, Draw Site Incubated
Also known as: TB Gold, QFT Gold Plus, QFT TB, QFT Plus, IGRA
Use
QuantiFERON‑TB Gold Plus (QFT‑Plus) is an interferon‑gamma release assay (IGRA) intended as an in vitro diagnostic aid for the detection of Mycobacterium tuberculosis infection, including both latent and active TB. It utilizes ESAT‑6 and CFP‑10 peptides to stimulate T cells in heparinized whole blood and measures interferon‑γ response via ELISA, reflecting cell‑mediated immune activity. Results should be interpreted in conjunction with risk assessment, radiography, and other diagnostic evaluations. The 4‑tube, site‑incubated format includes CD4+ and CD8+ T‑cell evaluation for a broader immune response assessment and is appropriate for immunocompromised patients and children aged 2 and older. It does not differentiate active from latent TB infection.
Special Instructions
Flexible collection options between 1 or 4 tubes; this version is 4‑tube and draw site incubated. Option for electronic result delivery directly to EHR. Sample tubes must be handled per instructions to preserve stability (refrigerated up to 48 hours). Control tubes (nil, mitogen, TB1, TB2) must meet validity criteria. Results may be indeterminate if control values are out‑of‑range. Not to be used for therapy monitoring.
Limitations
Cannot distinguish active TB disease from latent infection. Indeterminate results may occur if control tube values fall outside specified thresholds (eg, nil > 8.0 IU/mL, mitogen not ≥ 0.5 IU/mL above nil). Immune‑modulating therapies or compromised immune status may lead to unreliable results. Pre‑analytical factors such as improper mixing, temperature deviations, or delayed incubation can affect outcomes. Not valid for monitoring treatment response.
FDA Approved
Methodology
Immunoassay (ELISA)
Biomarkers
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
Not provided
Minimum Volume
Not provided