TB Test Practice and Application 5

Question 1

A TST is read at 96 hours instead of the recommended 48–72 hours. The induration measures 8 mm. How should this be handled?

Accepted Answer

Document the late reading with the measurement and note the timing; clinical judgment applies

Answer

Although 48–72 hours is optimal, readings up to 96 hours are generally acceptable; the result should be documented with a note about timing and clinician judgment applied.

Question 2

An employee conversion is defined as a TST change from negative to positive. What minimum increase in induration is typically required to classify a change as a true conversion?

Accepted Answer

An increase of 10 mm or more within a 2-year period

Answer

A TST conversion is generally defined as an increase of 10 mm or more within a 2-year period, helping distinguish true new infection from normal variation.

Question 3

Which of the following correctly describes the proper disposal of supplies after a TST administration?

Accepted Answer

Discard the uncapped needle directly into a sharps container without recapping

Answer

OSHA guidelines recommend discarding needles uncapped directly into a sharps container to prevent needlestick injuries; recapping with a one-hand scoop is acceptable only when necessary.

Question 4

A healthy US-born adult with no known TB risk factors and no occupational exposure has a TST induration of 14 mm. How is this result classified?

Accepted Answer

Negative; the threshold for low-risk individuals is 15 mm

Answer

For low-risk individuals with no TB risk factors, the positive TST threshold is 15 mm; 14 mm is therefore negative.

Question 5

A child recently arrived from a country with high TB prevalence. A TST is ordered. Which additional test is essential if the TST is positive?

Accepted Answer

Chest X-ray to rule out active TB disease

Answer

A positive TST in a child from a high-prevalence country requires a chest X-ray to exclude active pulmonary TB before diagnosing LTBI.

(TB Test) Tuberculosis Test Certification Practice Test

(TB Test) Tuberculosis Test Certification Practice Test

TB Test Practice and Application 5