The objective of this study was to compare characteristics of Direct and Concentrated Flurochrome (auramine-rhodamine) smears for the detection of Mycobacterium sp. and the direct microscopically examination, the concentration method and culture. A total of 900 sputum specimens from patients diagnosed with pulmonary tuberculosis were tested for the presence of mycobacteria. In this study we used the direct staining and an improved technique after treating the smears with N-acetyl-L-cysteine, NaOH and sodium citrate and concentration of bacteria by centrifugation. Specimens were stained using the auramine-rhodamine technique. The gold standard was defined as a positive Löwenstein-Jensen culture, or a positive AFB smear of material obtained from a negative culture after 60 days. Fifty two specimens were positive according to the gold standard definition. Decontamination and concentration of the sample increased the sensitivity of the direct microscopically examination from 71.1 to 88.4%. The concentration method adds significantly to the sensitivity of the direct microscopic examination, without much extra input.
