Test Details: AFB stain is a Gold standard test for diagnosing the presence of Acid-fast bacilli by microscopy. The conventional smear microscopy with the Ziehl-Neelsen (ZN) stain is a rapid and practical method for detecting acid-fast bacilli (AFB) in the smear with a rapid result, low cost and high positive predictive value for tuberculosis. 5 day early morning sputum specimen collection protocol helps to enhance sensitivity and to rule out false negative results.