TB Test Assessment and Evaluation 4

Question 1

Which chest X-ray finding in a TB-exposed, TST-positive patient is MOST consistent with primary TB infection in childhood rather than reactivation TB?

Accepted Answer

Ghon complex with calcified hilar lymph nodes

Answer

A Ghon complex (calcified primary focus with calcified hilar lymph node) is the hallmark radiographic remnant of healed primary TB infection.

Question 2

A serial TST program documents a healthcare worker's TST increasing from 0mm to 10mm over a 2-year period. CDC defines TST conversion as:

Accepted Answer

Any increase of ≥5mm in TST induration within a 2-year period

Answer

CDC defines TST conversion as an increase of ≥10mm within 2 years, but many programs also use ≥5mm increase in high-risk settings.

Question 3

Which of the following correctly describes the T-SPOT.TB assay methodology?

Accepted Answer

Peripheral blood mononuclear cells are isolated and spot-forming cells counted via ELISPOT

Answer

T-SPOT.TB uses ELISPOT technology to count individual IFN-γ-secreting T-cells (spot-forming units) in isolated PBMCs stimulated with ESAT-6 and CFP-10.

Question 4

A school-aged child with no risk factors has a TST of 8mm induration. What is the correct interpretation per CDC guidelines?

Accepted Answer

Negative — the threshold for low-risk individuals is ≥15mm

Answer

For low-risk individuals including healthy children with no TB risk factors, the positive TST threshold remains ≥15mm.

Question 5

During TST administration, the nurse inadvertently injects the tuberculin subcutaneously. What is the appropriate action?

Accepted Answer

Document the error, do not retest the same site, and repeat at a new site after 1 week

Answer

A subcutaneous injection is invalid; the test must be repeated at a different site, typically waiting at least 1 week to avoid confounding reactivity.

(TB Test) Tuberculosis Test Certification Practice Test

(TB Test) Tuberculosis Test Certification Practice Test

TB Test Assessment and Evaluation 4