External quality control for Acid Fast Bacilli Microscopic Examination of Hospital in the North of Thailand 2009

Abstract

          Acid fast bacilli microscopic examination was a component of DOTS (Directly Observed Treatment, Short Course) strategy for tuberculosis control program in Thailand since 1996. The quality of routine microscopic examination was evaluate d by external quality control system form do beginning of year 2009. Lot Quality Assurance Sampling (LQAS) was used for sampling hospital's routine acid fast bacilli microscopic slides to re-check agreement at 10th zonal tuberculosis center. The feed-back sheets about possibility of agreement reading result or other advisory items were sent to each hospital for improving routine quality examination. Thus, The improvement of careful produce examination was aroused and sloved cause of error problem to make better quality diagnosis system. Cumulative quality data of many hospital also showed total situation at the Province level for fortune management next.

The quality evaluation show 39 of 43 hospital (91%) cloud pass criteria of good quality reading results. Four hospital did not sending enough slides of total 108 slides per year (LQAS’s statistic calculation) that making four zero on four null evaluation. The 100% agreement reading results were 12 hospital while 99%, 96-98%, 90-95% were 10, 11, 6 hospital respectivery. High false microscopic examination was done for 5 these 5 hospital at the beginning of 2010. So carefulness is needed for reading slides to reduce high false negative and high false positive result that making lower tuberculosis infection unnecessary treatments.