Which is a type of test used for tuberculosis detection?

The caudal fold test is a specific method used to detect tuberculosis, particularly in animals like cattle. This test involves the intradermal injection of a purified protein derivative (PPD) that stimulates an immune response if the animal is infected with Mycobacterium bovis, the bacteria that causes tuberculosis in livestock. The reaction is observed at the site of injection after a specified period, and swelling indicates a positive response to the presence of the bacteria.

Other options, such as the blood smear test, urinalysis, and rapid antigen test, are not standard methods for tuberculosis detection. Blood smear tests are typically used for diagnosing other infections, urinalysis focuses on kidney and urinary tract conditions, and rapid antigen tests are more commonly associated with other pathogens, not tuberculosis. Thus, the caudal fold test stands out as the appropriate choice specifically for detecting tuberculosis in the relevant contexts.