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Latent tuberculosis — SCE Respiratory MCQ

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HardRespiratory InfectionsLatent tuberculosisSCE Respiratory

During treatment for MAC pulmonary disease, monthly sputum samples become negative in January, February and March and remain negative thereafter. Using the BTS definition, from which point is culture conversion dated and how long should treatment continue?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Conversion is dated in January and treatment continues for at least twelve months beyond it

Explanation lettering: E = shown as A · D = shown as C · C = shown as D · A = shown as E

D is correct. BTS defines culture conversion as three consecutive negative mycobacterial sputum cultures collected over at least three months, dated to the first of those negative cultures. Here conversion is therefore January. MAC therapy should continue for a minimum of 12 months after culture conversion. A negative smear is not equivalent to a negative culture, the date is not shifted to the second or third specimen, and routine completion bronchoscopy is unnecessary when serial expectorated cultures provide the required microbiological endpoint.

Reference: https://www.brit-thoracic.org.uk/document-library/guidelines/ntm/bts-ntm-guideline-summary-of-recommendations/