Smear-negative pulmonary tuberculosis.

Tuberculosis (TB) is the second leading cause of death from an infectious disease worldwide, after the human immunodeficiency virus. There are almost 2.5 million new smear-positive pulmonary TB cases and 1.9 million new smear-negative pulmonary TB cases in the world in 2012 according to the World Health Organization (WHO) Global Tuberculosis Report 2013. Smear negativity in pulmonary TB is a common clinical problem. Clinicians have difficulty in diagnosing smear-negative pulmonary TB without bacteriological confirmation. It is very important to decide whether or not to treat a patient with smear negative pulmonary TB when the culture results are pending or negative. New diagnostic methods are required for the diagnosis of smear-negative pulmonary TB. In addition to the development of new microbiological and serological diagnostic tests, clinical prediction scoring systems and algorithms including clinical and radiological findings of smear-negative pulmonary TB patients in our country, should be established to facilitate the diagnosis of smear-negative pulmonary TB.