TB Test Practice and Application 4

Question 1

A corrections officer with no previous TST on record tests negative on a first TST. Two weeks later, a second TST measures 12 mm. How should this two-step result be interpreted?

Accepted Answer

Baseline positive due to booster phenomenon; not a new conversion

Answer

New TB infection requiring immediate treatment

Answer

Invalid result; two-step testing is not recommended

Answer

Positive conversion; start contact investigation

Question 2

A patient's IGRA result is reported as 'indeterminate.' What is the most appropriate next step?

Accepted Answer

Repeat the IGRA or perform a TST

Answer

Assume the patient is TB-infected and start LTBI treatment

Answer

Report the result as negative and release the patient

Answer

Order a sputum culture to confirm

Question 3

Which finding distinguishes active TB disease from latent TB infection (LTBI)?

Accepted Answer

Active TB causes symptoms and is infectious; LTBI is asymptomatic and non-infectious

Answer

Active TB shows a positive TST; LTBI shows a negative TST

Answer

Active TB requires a sputum culture; LTBI requires only a chest X-ray

Answer

Active TB is always drug-resistant; LTBI is always drug-susceptible

Question 4

A nurse administers a TST and the patient immediately develops a large wheal with surrounding redness. The patient reports feeling faint. What condition should the nurse suspect?

Accepted Answer

Anaphylaxis requiring emergency response

Answer

A normal strong TST reaction

Answer

A positive TST result that must be documented

Answer

Subcutaneous injection artifact

Question 5

For which patient population is serial annual TST or IGRA screening typically recommended?

Accepted Answer

Healthcare workers with occupational exposure to TB patients

Answer

All US adults over age 65

Answer

Individuals who completed LTBI treatment within the past 2 years

Answer

US-born individuals with no known TB risk factors

Question 6

A patient with a positive TST has a normal chest X-ray and no TB symptoms. What is the appropriate clinical management?

Accepted Answer

Evaluate for LTBI and consider treatment with isoniazid or rifapentine-based regimen

Answer

No treatment needed since chest X-ray is normal

Answer

Repeat TST in 3 months to confirm

Answer

Initiate four-drug regimen for active TB

Question 7

Which of the following best describes the purpose of a TB risk assessment prior to skin testing?

Accepted Answer

To identify contraindications and determine the appropriate positive threshold

Answer

To eliminate the need for a skin test if risk is low

Answer

To prescribe prophylactic isoniazid before testing

Answer

To determine whether BCG vaccination is needed