Quality indicators in a mycobacteriology laboratory supporting clinical trials for pulmonary tuberculosis

Abstract

Background: Documentation of structured quality indicators for mycobacteriology laboratories supporting exclusively controlled clinical trials in pulmonary tuberculosis (PTB) is lacking. Objective: To document laboratory indicators for a solid (Lowenstein–Jensen medium) culture system in a mycobacteriology laboratory for a period of 4 years (2007–2010). Methods: The sputum samples, collected from PTB suspects/patients enrolled in clinical trials, were subjected to fluorescence microscopy, culture and drug sensitivity testing (DST). Data was retrospectively collected from TB laboratory registers and computed using pre-formulated Microsoft Office Excel. Laboratory indicators were calculated and analyzed. Results: The number of samples processed in a calendar year varied from 6261 to 10,710. Of the samples processed in a calendar year, specimen contamination (4.8–6.9%), culture positives (78.4–85.1%) among smear positives, smear positives (71.8–79.0%) among culture positive samples, smear negatives among culture negative samples (95.2–96.7%), and average time to report DST results (76–97 days) varied as shown in parentheses. Conclusion: Values of quality indicators in mycobacteriology laboratories supporting exclusively clinical trials of PTB have to be defined and used for meaningful monitoring of laboratories.

Keywords

• Quality assurance
• Mycobacterium tuberculosis
• Laboratory indicator
• Pulmonary tuberculosis