T‑SPOT®.TB
Also known as: TSPOT, IGRA, TBSPOT, T-SPOT.TB, T SPOT
Use
The T‑SPOT.TB assay is an interferon-gamma release assay (IGRA) used to aid in the diagnosis of Mycobacterium tuberculosis infection by detecting effector T‑cells responding to TB-specific antigens ESAT‑6 and CFP‑10, in conjunction with clinical and radiographic evaluation; it cannot distinguish latent from active infection. Interpretation categories include positive, negative, borderline, or invalid. Clinical use includes screening individuals 2 years and older, immunocompromised patients, BCG-vaccinated individuals, and those requiring immigration exam testing.
Special Instructions
Requires a single patient visit for whole blood collection in a lithium or sodium heparin green-top tube (no gel), strict ambient handling (do not refrigerate, freeze, or centrifuge), preferably using Quest T‑Spot shipping kit; specimens must be received within up to 54 hours at ambient temperature.
Limitations
The test is indirect and cannot distinguish active from latent TB infection; borderline or invalid results require repeat testing; immunocompromised status may affect sensitivity; operator and specimen handling errors can cause invalid results; test should be interpreted with clinical context; not evaluative for treatment monitoring.
FDA Approved
Methodology
Immunoassay (Multiplex Protein Panel)
Biomarkers
LOINC Codes
- 71773-6
Result Turnaround Time
1-10 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
Adults ≥10 y: 6 mL (minimum 6 mL); Pediatrics 2‑9 y: 4 mL; <2 y: 2 mL; Immunocompromised ≥10 y: 9 mL
Minimum Volume
As above
Container
Greiner 9 mL lithium heparin (green‑top) tube (no gel); sodium heparin acceptable
Collection Instructions
Inverse gently after collection; use Quest T‑Spot shipping kit; do not centrifuge; ship same day
Storage Instructions
Strict ambient only; do not refrigerate or freeze
Causes for Rejection
Use of anticoagulants other than lithium/sodium heparin; hemolysis; centrifuged; refrigerated or frozen; gel tubes
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Up to 54 hours |
| Refrigerated | Unacceptable |
| Frozen | Unacceptable |