The most common way doctors diagnose tuberculosis (TB) is through the TB skin test, also known as the Mantoux tuberculin skin test. This widely used diagnostic method plays a crucial role in identifying potential TB infection.
The Mantoux Tuberculin Skin Test Explained
The TB skin test is a straightforward procedure designed to detect if a person has been infected with Mycobacterium tuberculosis, the bacterium that causes TB. It does not indicate whether the infection is active or latent, but rather exposure.
How the Test is Performed:
- Preparation: A healthcare professional will prepare the injection site, usually on your forearm.
- Injection of Tuberculin: A tiny amount of fluid, known as tuberculin, is injected just below the skin's surface in your forearm.
- This fluid contains some inactive TB protein, which helps the body react if it has previously encountered the TB bacteria.
- Sensation: You should only feel a small prick from the needle during the injection.
- Reading the Test: After the injection, you will need to return to the doctor or clinic within 48 to 72 hours for the test to be read. The healthcare provider will measure any induration (a firm, raised area) at the injection site to determine the result.
| Test Name | Primary Purpose | Method | Key Characteristic |
|---|---|---|---|
| TB Skin Test | Diagnosing TB infection (exposure) | Injection of tuberculin (inactive TB protein) just below the skin | Most common diagnostic method |
| (Mantoux Tuberculin Skin Test) | (Not to determine active vs. latent) | (Observation of reaction after 48-72 hours) |
While the TB skin test is the most common initial diagnostic approach, further tests may be required to confirm active disease, such as chest X-rays, blood tests (like IGRA), or sputum cultures, depending on the individual's risk factors and test results.
