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Tuberculosis Interferon Gamma Release Assay (TSPOT)
MessageThis specimen must be processes as a Limited Stability Sample. Draw sample Monday through Thursday before noon. Notify sendout department at NCMC 970-810-6400 that specimen will be coming. Specimen must be received at NCMC by 1:00 PM. STAT courier may be necessary.
ESOT
Test Name: Tuberculosis Interferon Gamma Release Assay (TSPOT)
Reference Lab: NJEW
Test Code: TSPOT
Specimen: 10 mL whole blood from Green top tube (sodium heparin)
Handling Requirements: Do not centrifuge, send ambient.
ESOT
Test Name: Tuberculosis Interferon Gamma Release Assay (TSPOT)
Reference Lab: NJEW
Test Code: TSPOT
Specimen: 10 mL whole blood from Green top tube (sodium heparin)
Handling Requirements: Do not centrifuge, send ambient.
Test Code
PESOT - TSPOT - NJEW
Alias/See Also
T-Spot
CPT Codes
86481
Preferred Specimen
10 mL whole blood from Green top tube (sodium heparin)
Minimum Volume
6 mL
Instructions
- Do NOT centrifuge
- Keep at room temperature (18-22°C).
- Samples must arrive within 24 hours of draw and are accepted Monday through noon on Friday.
- Customer service will contact National Jewish Lab 1-800-550-6227 to notify specimen is coming.
Specimen Stability
24 hours at room temperature (18-22°C).
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Frozen, clotted, hemolyzed, spun down, citrate anticoagulant (blue top)
Methodology
Elispot
Setup Schedule
Mon-Thur
Report Available
48 hours
Reference Range
Negative
Interpretive Data
The T-SPOT.TB test is based on the measurement of a cell mediated response to Mycobacterium tuberculosis-specific antigens (ESAT-6 and CFP-10). Peripheral blood mononuclear cells (PBMC) are separated from whole blood and incubated in plates coated with anti-interferon gamma (IFNg) antibodies with these antigens for 16-24 hours. Following incubation, IFNg-producing cells are detected using a second anti- IFNg antibody, an enzyme linked conjugate, and substrate. Controls include unstimulated cells (Nil control) and phytohemagglutinin stimulated cells (Mitogen control). A test is considered positive or borderline when IFNg- spot forming units (SFU) produced in response to either of the TB antigens is significantly greater than the Nil control (TB-Nil; positive = > 8 SFU, borderline = 5, 6 or 7 SFU), and the Mitogen control has a robust IFNg response. The T-Spot.TB result is indeterminate if the Nil control is high (>10 SFU) or the mitogen control is low (< 20 SFU). Although the test is reported qualitatively, IFNg SFU for the individual test conditions are also reported as recommended by the Centers for Disease Control and Prevention.1
The T-Spot.TB detects infections due to M. tuberculosis complex (M. tuberculosis, M. bovis and M. africanum). BCG strains and nontuberculous mycobacteria with the exception of M. marinum, M. kansasii, M. szulgai and M. gordonae do not express ESAT-6 and CFP-10 proteins. Therefore, patients either vaccinated with BCG or infected with most nontuberculous mycobacterial strains should test negative.
T-Spot.TB results should always be interpreted in conjunction with clinical and other relevant laboratory findings.
1 Guidelines for Using the QuantiFERON®-TB Gold Test for Detecting Mycobacterium tuberculosis Infection, United States. Centers for Disease Control and Prevention. Morbidity and Mortality Weekly Report (MMWR). December 16, 2005 / 54(RR15);49-55
Interpretive Data
The T-SPOT.TB test is based on the measurement of a cell mediated response to Mycobacterium tuberculosis-specific antigens (ESAT-6 and CFP-10). Peripheral blood mononuclear cells (PBMC) are separated from whole blood and incubated in plates coated with anti-interferon gamma (IFNg) antibodies with these antigens for 16-24 hours. Following incubation, IFNg-producing cells are detected using a second anti- IFNg antibody, an enzyme linked conjugate, and substrate. Controls include unstimulated cells (Nil control) and phytohemagglutinin stimulated cells (Mitogen control). A test is considered positive or borderline when IFNg- spot forming units (SFU) produced in response to either of the TB antigens is significantly greater than the Nil control (TB-Nil; positive = > 8 SFU, borderline = 5, 6 or 7 SFU), and the Mitogen control has a robust IFNg response. The T-Spot.TB result is indeterminate if the Nil control is high (>10 SFU) or the mitogen control is low (< 20 SFU). Although the test is reported qualitatively, IFNg SFU for the individual test conditions are also reported as recommended by the Centers for Disease Control and Prevention.1
The T-Spot.TB detects infections due to M. tuberculosis complex (M. tuberculosis, M. bovis and M. africanum). BCG strains and nontuberculous mycobacteria with the exception of M. marinum, M. kansasii, M. szulgai and M. gordonae do not express ESAT-6 and CFP-10 proteins. Therefore, patients either vaccinated with BCG or infected with most nontuberculous mycobacterial strains should test negative.
T-Spot.TB results should always be interpreted in conjunction with clinical and other relevant laboratory findings.
1 Guidelines for Using the QuantiFERON®-TB Gold Test for Detecting Mycobacterium tuberculosis Infection, United States. Centers for Disease Control and Prevention. Morbidity and Mortality Weekly Report (MMWR). December 16, 2005 / 54(RR15);49-55
Performing Laboratory
National Jewish Laboratory - Immunology Lab
