Tuberculosis

T-SPOT®.TB

		Test Overviews
		How It Works
		The Science
		Clinical Data

		About Tuberculosis
		Active TB Disease and Latent TB Infection
		Diagnosing Tuberculosis
		Why Choose T-SPOT®.TB
		TB Vaccination & Treatment
		Patient Groups
		Patient FAQs

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The World Health Organization (WHO) estimates that more than one third of the world’s population is infected with Mycobacterium tuberculosis.

Test Overview: TB Skin Test Vs T-SPOT®.TB

The TB skin test (Tuberculin skin test) has been in existence for over 100 years. The accuracy of the TB skin test varies and can be affected by a previous BCG vaccination, a weakened immune system and by other illnesses or medical treatments.

Both tests identify LTBI by using the body's immune response to TB proteins, whether the person is showing signs and symptoms of TB disease or not.

Tuberculin Skin Test

T-SPOT.TB

False Positives

BCG vaccination
Environmental mycobacterium

T-SPOT.TB is very specific:

Specificity approaching 100%
Not affected by BCG vaccination
Does not cross-react with common environmental mycobacterium

False Negatives

Skin reaction is a mixed immune response (problem in immunosuppressed patients)
Often negative in active disease (75-90% sensitivity, lower in immunosuppressed).

T-SPOT.TB is very sensitive:

Sensitivity ~95%
Identifies infected subjects missed by TST
Immunosuppression has little effect
Performance maintained in infants
High sensitivity in active TB, including extrapulmonary TB

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