TB Test Core Knowledge and Fundamentals 5

Question 1

Which of the following best explains why BCG vaccination can cause a false-positive TST?

Accepted Answer

BCG contains live attenuated Mycobacterium bovis antigens that cross-react with tuberculin PPD

Answer

BCG is made from M. bovis and shares antigens with M. tuberculosis PPD, causing sensitization that can produce a positive TST in vaccinated individuals.

Question 2

A person with no symptoms has a positive IGRA. The next recommended step is:

Accepted Answer

Chest X-ray to rule out active TB disease

Answer

A positive IGRA indicates TB infection; a chest X-ray is needed to exclude active disease before classifying as LTBI and considering preventive therapy.

Question 3

Extrapulmonary TB most commonly affects which site?

Accepted Answer

Lymph nodes (lymphadenitis)

Answer

Lymph node TB (scrofula) is the most common extrapulmonary manifestation, especially in children and immunocompromised individuals.

Question 4

Pulmonary TB is considered potentially infectious until the patient has met all of the following EXCEPT:

Accepted Answer

TST converts from positive to negative

Answer

TST conversion is not a criterion for determining infectiousness; clinical response, smear negativity, and treatment duration are the relevant markers.

Question 5

Which of the following populations is at highest risk for progressing from LTBI to active TB disease?

Accepted Answer

People living with HIV who are not on antiretroviral therapy

Answer

Untreated HIV infection dramatically impairs cell-mediated immunity, increasing the annual risk of TB reactivation to 5–10% (vs. 5–10% lifetime risk in immunocompetent persons).

(TB Test) Tuberculosis Test Certification Practice Test

(TB Test) Tuberculosis Test Certification Practice Test

TB Test Core Knowledge and Fundamentals 5