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

ABSTRACT

Documentation of structured quality indicators for mycobacteriology laboratories supporting exclusively controlled clinical trials in pulmonary tuberculosis [PTB] is lacking. To document laboratory indicators for a solid [Lowenstein-Jensen medium] culture system in a mycobacteriology laboratory for a period of 4 years [2007-2010]. 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. 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. Values of quality indicators in mycobacteriology laboratories supporting exclusively clinical trials of PTB have to be defined and used for meaningful monitoring of laboratories.