Aim: to develop an assay system of a radioisotope (32P)-based PCR dot-blot hybridization technique and evaluation of the assay directly for TB sputum samples to detect mutation at codon 306 of embB gene of Mycobacterium tuberculosis related with ethambutol (EMB) resistance. Methods: one hundred and sixteen of sputum samples were used in this study. Bacterial genome in sputum samples was extr…