Which test involves injecting a small amount of tuberculin under the skin to check for a reaction?
The Mantoux TST is a widely used diagnostic test where tuberculin is injected under the skin. A raised, hard area at the injection site after 48-72 hours indicates a positive result, suggesting TB exposure.
Which of the following is an Interferon-Gamma Release Assay (IGRA)?
QuantiFERON-TB Gold is an IGRA that measures the immune system’s release of interferon-gamma when exposed to TB antigens. It is a blood test used as an alternative to the TST.
What is the purpose of a chest X-ray in TB diagnosis?
A chest X-ray is used when there is a positive TST or IGRA result. It helps visualize the lungs to identify signs of active TB, such as infiltrates or cavities.
Which TB test is most appropriate for someone vaccinated with BCG?
The QuantiFERON-TB Gold test is not affected by prior BCG vaccination, making it suitable for distinguishing latent TB from vaccine effects.
What does a positive Mantoux Tuberculin Skin Test indicate?
A positive TST indicates that the person has been exposed to TB bacteria and may have a latent infection. Further tests are needed to confirm active TB disease.