Tuberculosis
Tuberculosis ( 23 Questions)
A skin test result with an induration of 10 mm is considered positive in certain populations, indicating an active TB infection. These populations include people with known close contact with TB-infected individuals, HIV-positive individuals, recent immigrants from high-prevalence countries, and those with chest X-ray findings consistent with previous TB. The positive result means that the person has been exposed to the TB bacteria and has developed a delayed hypersensitivity reaction to the purified protein derivative (PPD) injected during the skin test.
A negative reaction, indicating no TB infection, would typically be a skin induration of less than 5 mm. In this case, with an induration of 10 mm, a negative reaction can be ruled out.
An induration of 10 mm is not considered an inconclusive result. Inconclusive results are usually associated with very small indurations or circumstances where there is uncertainty about the interpretation of the test.
A borderline reaction is not typically associated with TB testing. Borderline reactions are less specific and are not commonly used to interpret the results of TB skin tests.
Choice A rationale:
A skin test result with an induration of 10 mm is considered positive in certain populations, indicating an active TB infection. These populations include people with known close contact with TB-infected individuals, HIV-positive individuals, recent immigrants from high-prevalence countries, and those with chest X-ray findings consistent with previous TB. The positive result means that the person has been exposed to the TB bacteria and has developed a delayed hypersensitivity reaction to the purified protein derivative (PPD) injected during the skin test.
Choice B rationale:
A negative reaction, indicating no TB infection, would typically be a skin induration of less than 5 mm. In this case, with an induration of 10 mm, a negative reaction can be ruled out.
Choice C rationale:
An induration of 10 mm is not considered an inconclusive result. Inconclusive results are usually associated with very small indurations or circumstances where there is uncertainty about the interpretation of the test.
Choice D rationale:
A borderline reaction is not typically associated with TB testing. Borderline reactions are less specific and are not commonly used to interpret the results of TB skin tests.