Risk for Tuberculosis Transmission: NAAT More Sensitive than AFB Smear

In a retrospective study, the minimum transmission estimate was 5.2% for the nucleic acid amplification test versus 11.2% for triplicate acid-fast bacilli smear.

Triplicate acid-fast bacilli (AFB) smears have been the standard to ascertain tuberculosis (TB) transmissibility. However, smear-negative persons may contribute up to 17% of cases of TB transmission. Nucleic acid amplification tests (NAATs) appear to be intermediate in sensitivity between culture and AFB smear for detecting TB. In this study, researchers used retrospective data from a large public health program from January 2004 through September 2009 to determine the risk for TB transmission in subjects with negative NAAT versus negative AFB smears. To ascertain if cases were associated with a cluster, genotyping was performed. A minimum transmission risk was calculated.

There were 809 cases of culture-confirmed TB. For NAAT analysis, 49 c…

Reviewing Author

Neil M. Ampel, MD

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Editorial BoardsUpToDate

Leadership Positions in Professional SocietiesCoccidioidomycosis Study Group (Past President, Secretary, Treasurer)

Neil M. Ampel, MD

Disclosures

Editorial BoardsUpToDate

Leadership Positions in Professional SocietiesCoccidioidomycosis Study Group (Past President, Secretary, Treasurer)

Risk for Tuberculosis Transmission: NAAT More Sensitive than AFB Smear

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Reviewing Author