The Value of Using Tagman Real-time PCR, Phenol-Auramine Stain and Ziehl-Neelsen Stain in The Diagnosis of Pulmonary Tuberculosis in Fine-Needle Aspiration Material

Pulmonary tuberculosis represents a growing health problem among Iraqi population with the emergence of an increasing number of new cases each year. The diagnosis of tuberculosis relies upon the identification of TB bacilli in the sputum of suspected patients, traditionally done by Ziehl-Neelsen (ZN) stain, along with other diagnostic modalities including culture, PCR study and phenol auramine (PA) stain, nevertheless; some patients may present with advanced disease (post primary, lung mass or cavitary lesions with mediastinal lymphadenopathy), sometimes mimicking lung tumours, necessitating fine needle aspiration (FNA) to exclude other pathologies. In order to evaluate the usefulness of different real-time PCR, PA and ZN stains, 102 patients subjected to fine needle aspiration were included in this study. Tagman real-time PCR, PA stain and ZN stain were applied to 23 out of 102, in which malignancy was excluded and the diagnosis of tuberculosis was suspicious. Tagman real-time PCR was highly accurate, specific and sensitive (100%), while both PA and ZN stain revealed sensitivity, specificity and accuracy of 54.5% vs. 45.4%, 35.9% vs. 27.77%, and 78.2% vs. 73.9% respectively.