Study of More-Sensitive TB Test Found Positive TB Results Far More Prevalent Than Expected

Studies of a couple of cohorts of patients found incidence rate of between 12 and 16 percent.

April 15, 2026

2 min read

Key Highlights

A highly sensitive TB test detected TB DNA in 12.3% of hospitalized patients, much higher than the 2% in controls.
The study suggests the existence of a previously unrecognized form of TB, called paucibacillary TB, with bacterial levels too low for conventional detection.
Results imply that many TB cases in the U.S. may go undiagnosed, representing the hidden part of the 'iceberg' of TB infections.
Most TB cases in the U.S. are reactivations of infections acquired years earlier, complicating diagnosis and control efforts.
Further large-scale research is needed to confirm these findings and potentially reshape TB diagnostic strategies.

A highly sensitive test for tuberculosis detected Mycobacterium tuberculosis DNA in a “surprising proportion of hospitalized patients,” according to a study published in Nature Communications. CIDRAP has the news.

Researchers tested 146 anonymized respiratory samples collected at two Boston hospitals in 2013 and 50 control samples collected in 2014. TB DNA was found in 12.3% of the former group, compared with 2% of control samples. A follow-up cohort returned a 15.8% positivity rate. This incidence rate is “far higher than expected.”

Most new TB cases in the U.S. come from “infections that were picked up years earlier and then reactivated later in life.” The researchers hypothesize that the prevalence of positive tests in these results may “point to a previously unrecognized form of TB, referred to as paucibacillary TB disease, in which bacterial levels are too low to be detected by conventional TB tests.”

The senior author of the study said that these results open the possibility that “there could be thousands of Americans infected with forms of tuberculosis disease that remain hidden from our current diagnostic tools.” The findings may be evidence of the so-called “’iceberg principle,’ in which U.S. TB cases that are diagnosed using standard TB tests represent the visible tip of the iceberg, while many more cases are hidden below the surface.” Larger studies are required to confirm this study’s findings.