Investigation of the Necessity of Petroff Method for More Accurate Diagnosis of Tuberculosis in Tuberculosis Reference Laboratory of Hamadan Province, Iran, During the COVID-19 Pandemic

Background and Objective: A definitive diagnosis of tuberculosis is based on the identification of tubercle bacilli in sputum using microscopy and culture. Although direct smear microscopy is the most common diagnostic method, the Petroff method is recommended for a better diagnosis of tuberculosis. This study aimed to evaluate the Petroff method for a more accurate diagnosis of tuberculosis in health centers of Hamadan province, Iran, during the COVID-19 pandemic. Materials and Methods: In this descriptive cross-sectional study, 210 sputum specimens from patients who were referred to the tuberculosis reference laboratory in Hamadan province were collected in health centers. All of the samples were processed for the presence of mycobacteria using the Petroff method and the direct smear technique, and the results of both techniques were compared afterward. Results: Among 210 samples, 9 (4.28%) and 12 (5.71%) cases were reported as smear-positive samples by direct smear method and Petroff method, respectively. A comparison of the results showed that the sensitivity for acid-fast bacilli (AFB) smears was increased using the Petroff method. Conclusion: Petroff method improved the sensitivity of AFB identification. It was methodologically simpler and less expensive and can be used as a promising candidate in primary TB control programs. Therefore, we recommend the Petroff method for the improvement of the sensitivity of AFB microscopy