What type of diagnostic test is primarily used to detect tuberculosis (TB)?

The skin test, commonly known as the Mantoux test, is primarily used to detect tuberculosis (TB) because it measures the body's immune response to a specific protein derived from the Mycobacterium tuberculosis bacteria. This test involves the intradermal injection of purified protein derivative (PPD) and observing the reaction 48 to 72 hours later. A positive result indicates that the person has been exposed to TB bacteria and may either have active TB or latent TB infection.

While blood tests for TB, such as interferon gamma release assays (IGRAs), are also available and used in certain scenarios, the skin test is traditionally the standard method for screening individuals, particularly in high-risk populations. Chest X-rays are critical in evaluating individuals for active TB but are not used as a standalone test for initial detection. Urine tests are generally not effective for diagnosing TB, as the disease primarily affects the lungs and the sputum is the more relevant specimen for culture and molecular testing. The Mantoux test remains a cornerstone in TB screening and public health strategies aimed at controlling the disease.