Question

A healthcare worker has comes to the clinic for her annual TB test. Her history reveals that she has had prior bacillus calmette-guerin 9BCG) vaccine. What is the preferred method of TB testing for this patient?

a. Mantoux test
b. TB blood test
c. Chest x-ray
d. Patient is immune to TB, no testing needed

Answer 1

The preferred method of TB testing for a healthcare worker who has had the prior BCG vaccine is a TB blood test, as it provides accurate results unaffected by the vaccination.

Step-by-step explanation:

For a healthcare worker who has had prior bacillus Calmette-Guérin (BCG) vaccine, the preferred method of TB testing is a TB blood test. This is because the BCG vaccine can cause false-positive results in the standard Mantoux tuberculin skin test. Unlike the skin test, the TB blood test, also known as an interferon-gamma release assay (IGRA), is not affected by prior BCG vaccination and therefore can provide accurate results for individuals who have been vaccinated. While a chest x-ray can be required to confirm exposure if a skin test is positive, it is not the first step in testing. It is also important to note that no individual is immune to TB simply as a result of vaccination, so testing is definitely required.