FAQ


What is the scale of the tuberculosis (TB) problem?
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?
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?

 

What is the scale of the tuberculosis (TB) problem?

Although effective treatment has been available for over 70 years, tuberculosis (TB) remains the second leading cause of death from an infectious disease worldwide. The World Health Organization (WHO) estimates that more than one third of the world’s population is infected with Mycobacterium tuberculosis. TB continues to be a significant disease due to factors such as immigration, the emergence of drug resistant TB strains, HIV, and other conditions that weaken the immune system.(¹)

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Can I use the T-SPOT.TB test instead of the tuberculin skin test (TST)?

Yes. The Centers for Disease Control and Prevention (CDC) state in their updated guidelines that IGRAs (e.g. the T-SPOT.TB test) may be used in place of a TST in most 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 IGRAs an attractive diagnostic aide for detecting TB.²

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What are the limitations of the Tuberculin Skin Test (TST or PPD)?

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What are the advantages of the T-SPOT.TB test?

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Where can I send blood specimens for the T-SPOT.TB test?

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.

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Is the T-SPOT.TB test affected by previous BCG vaccination?

Unlike the TST, there is no association with BCG vaccination and T-SPOT.TB test results.¹ The test utilizes 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).

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How much blood do you need for the T-SPOT.TB test?

The guidelines for the volume of blood are:

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How will T-SPOT.TB test results be reported?

The T-SPOT.TB test results will be reported as positive, negative, borderline, or invalid. Spot counts are also reported.

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What do I do with a Borderline?

Borderline results are clinically meaningful and should be followed. Retesting by collecting another sample is recommended.

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What do I do with an Invalid test result?

Invalid results are not clinically interpretable and may 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.

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Is the T-SPOT.TB test covered by insurance?

Yes, the T-SPOT.TB test is covered by most insurance. The test is covered by a unique CPT® code: 86481

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Which blood collection tube should be used?

Collect the blood specimen(s) in a standard green top tube (lithium or sodium heparin). No special collection tubes are required.

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Can I use blood collection tubes that contain EDTA?

EDTA affects the secretion of interferon gamma. Blood collection tubes that contain this anti-coagulant cannot be used.

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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.

>Note: For immunocompromised individuals, collect double the recommended blood volume.