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Sputum PCR for TB Detection

November 28, 2012

Annual PCR-based screening of sputum for tuberculosis may reduce the prevalence of the disease, and drug-resistant forms of the disease, in prisons in the former Soviet Union, a new study in PLOS Medicine says. Technology Review's Susan Young notes that TB rates in such prisons are among the highest in the world. "These prisoners are 10 times more likely than the general population to have the disease and extremely likely to have a drug-resistant form of TB. This situation is a problem not only for the prisoners but also for the people that interact with them once they are freed," she adds.

Researchers led by Stanford University's Jeremy Goldhaber-Fiebert examined a number of different approaches, both alone and in combination, for TB screening and diagnosis: self-referral, symptom screening, mass miniature radiography, and sputum PCR. Then, they projected the 10-year costs, estimated the quality-adjusted life years saved, and determined the prevalence of TB and drug-resistant TB over that time frame. "The researchers used computer models to predict that [screening using Cepheid's] GeneXpert can reduce TB in inmates by nearly 20 percent within four years as long as patients are given the appropriate drug treatment," Young writes. The current approach is mass miniature radiography screening.


I am wondering why the use of

Submitted by eliot.jekowsky on Wed, 11/28/2012 - 14:11.

I am wondering why the use of PPDs is not part of the screening process for TB.

BCG (Bacille Calmette-Guérin)

Submitted by tskelton on Wed, 11/28/2012 - 14:49.

BCG (Bacille Calmette-Guérin) is a TB vaccine that can interfere with the interpretation of a PPD. BCG is not used as a vaccine in the United States, but it is often routinely administered in countries with a higher incidence of TB. Also, PPDs should not be performed when a person has had a previous positive reaction as they are more likely to have a severe local reaction.

That makes sense. Thanks.

Submitted by eliot.jekowsky on Thu, 11/29/2012 - 08:52.

That makes sense. Thanks.