1. Tuberculosis
Iran is considered a high-burden country for tuberculosis, with a notable incidence rate. The endemicity of TB in this region increases the pretest probability of the disease in patients presenting with compatible symptoms and radiological findings (3). Sputum smear microscopy and culture are commonly used for the diagnosis of pulmonary TB. However, it’s essential to recognize the limitations of these tests (5, 6).
Smear microscopy has a sensitivity ranging from 36.9% to 55.6% and specificity of around 99%, while culture has higher sensitivity (approximately 80-90%) but takes longer for results (7, 8). Importantly, negative smear and culture results do not exclude the diagnosis of TB, especially in cases of paucibacillary disease or extrapulmonary involvement (8).