What is the T-SPOT.TB test?
Can I use the T-SPOT.TB test instead of the tuberculin skin test (TST)?
What are the limitations of the tuberculin skin test (TST)?
What are the advantages of the T-SPOT.TB test?
Are there any patients that should be excluded from diagnosis with the T-SPOT.TB test?
Where can I send blood specimens for the T-SPOT.TB test?
Is the T-SPOT.TB test affected by previous BCG vaccination?
How much blood do you need for the T-SPOT.TB test?
How will the T-SPOT.TB test results be reported?
What do I do with a Borderline test result?
What do I do with an Invalid test result?
Is the T-SPOT.TB test covered by insurance?
Which blood collection tubes do I use?
Can I use blood collection tubes that contain EDTA?
What is the sensitivity and specificity of the T-SPOT.TB test?
The T-SPOT.TB test is a blood test, also known as an Interferon Gamma Release Assay, or IGRA, for TB infection. The test was approved by the FDA in 2008. The T-SPOT.TB test is an in vitro diagnostic test that enumerates the response of effector T cells that have been senstitized to Mycobacterium tuberculosis. The
T-SPOT.TB test 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.¹
Yes. The Centers for Disease Control and Prevention (CDC) state in their updated guidelines that IGRAs (e.g. the T-SPOT.TB test) can be used in all situations requiring TB testing.² The CDC states that IGRAs are preferred for BCG vaccinated individuals and for those persons who are unlikely to return for the reading of the test result.² In addition, the CDC states that the administrative and logistic difficulties associated with the skin test make the T-SPOT.TB test an attractive diagnostic aid for detecting TB.²
- Requires two visits
- Test results are affected by the BCG vaccine and immunosuppressive conditions
- Subjectivity due to inoculation technique and interpretation of results
- Accurate: The only TB test with sensitivity and specificity exceeding 95% in pivotal clinical trials¹
- Reliable: Even in challenging testing populations, including foreign-born and immunosuppressed persons¹
- Simple: Requires just one visit and one standard collection tube
No, the test can be used in screening of all at-risk groups.
Oxford Diagnostic Laboratories®, the only national TB testing service exclusively dedicated to performing the T-SPOT.TB test, has the ability to set up your facility through a simple process. Please contact Client Services at 1-877- 59 TBLAB to get started.
Unlike the TST, there is no association with BCG vaccination and T-SPOT.TB test results.¹ The test utilizies two M. tuberculosis specific antigens (ESAT-6 and CFP 10) that do not cross react with the BCG vaccine or most common non-tuberculosis mycobacteria (NTMs).
The guidelines for the volume of blood are:
- Adults and children ≥ 10 years of age: collect 6 mL
- Children ≥2 to <10 years of age: collect 4 mL
- Children <2 years of age: collect 2 mL
Note: For immunocompromised individuals, collect double the recommended blood volume.
The T-SPOT.TB test results will be reported as positive, negative, borderline, or invalid. Spot counts are also reported.
Borderline results are clinically meaningful and should be followed. Retesting by collecting another sample is recommended.
What do I do with an Invalid test result?
Invalid results are not clinically interpretable and occur if the positive and/or negative controls do not perform as expected. Retesting by collecting another sample is recommended.
Invalid results are uncommon and may be related to the immune status of the individual or a number of technical factors.
Yes, the T-SPOT.TB test is covered by most insurance. The test is covered by a unique CPT® code: 86481
EDTA affects the secretion of interferon gamma. Blood collection tubes that contain this anti-coagulant cannot be used.
¹T-SPOT.TB Package Insert
²CDC MMWR 2010;59 (No.RR-5): 1-25
CPT is a registered trademark of the American Medical Association
T-SPOT and Oxford Diagnostic Laboratories are registered trademarks of Oxford Immunotec Ltd.