Tuberculosis Guides
Tuberculosis (TB) testing.
What these guides cover
Tuberculosis guides cover TB blood testing (IGRA) and how it differs from a skin test. They explain who is typically screened, what a positive result means, and why follow-up with a clinician is essential.
Tuberculosis screening commonly uses an IGRA blood test, which measures the immune response to TB proteins rather than looking for the bacteria directly. It differs from the older skin test, which requires a return visit to read the result. A positive IGRA shows that the immune system has responded to TB proteins at some point; it does not by itself distinguish active disease from latent infection. Further evaluation by a clinician is needed after a positive screen.
How to use these guides
Each guide below focuses on a single test or a small group of related tests. Start with the marker you and your clinician have discussed, then follow the related-test links to see what is often ordered alongside it. Preparation and timing instructions appear in each guide, and where testing is available is listed by state and city. These guides are educational and do not replace advice from a healthcare provider.
Latent TB Testing: What a Positive Result Really Means
Learn what latent TB testing shows, how a positive result differs from active TB, who should be screened, and how to order TB testing at a l
Tuberculosis Blood Testing: IGRA Compared to Skin Tests
Learn how tuberculosis blood testing works, how it compares with the skin test, and how to order TB screening at a CLIA-certified lab near y
Tuberculosis FAQ
How does a TB blood test differ from a skin test?
An IGRA blood test measures the immune response in a blood sample and needs only one visit, while a skin test requires an injection and a return visit to read the reaction. Both are screening tests.
What does a positive TB test mean?
A positive result shows the immune system has responded to TB proteins at some point. It does not by itself tell active disease from latent infection, so a clinician arranges further evaluation.
Who is usually screened for TB?
Screening is often recommended for people with known exposure, certain occupational or travel risks, or before some treatments. A healthcare provider can advise whether screening applies to your situation.
Reviewed by the LabDirectories Editorial Team
Our team researches and fact-checks all content to ensure accuracy. We update guides regularly to reflect current testing options, pricing, and laboratory accreditation standards.