Therefore, although this method is not highly specific for TB diagnosis, CT adds diagnostic information and is a particularly valuable method for patients with suspected TB and negative AARB test results, allowing adequate therapeutic decision-making while waiting for sputum culture results to confirm TB [3-7].
The patients followed outpatient routines, including blood tests, collection of two AARB samples, Koch's bacillus (KB) culture, and imaging tests.
The inclusion criteria were clinical suspicion of TB with negative AARB test results, diagnostic confirmation by MTB culture in sputum, and performance of CT1 and CT2.
Previous studies have reported that the percentage of patients with active TB and negative AARB testing varies between 21% and 47% of cases, and some studies have emphasized the loss of assay sensitivity as a possible cause .
Several patients were referred after successive medical appointments; negative AARB test results in sputum as well as an incorrect diagnosis and treatment for pneumonia, which leads us to hypothesize that the main reasons are the lack of TB suspicion by physicians and a loss of sensitivity of sputum smear microscopy, which agrees with the results of previous studies [1, 2, 15].