Importance of quality control of baciloscopy in laboratories that perform diagnosis of tuberculosis

Baciloscopy is the primary tool for pulmonary tuberculosis diagnosis, being this technique the most used internationally in the search for infectious cases. Quality control is the process of the rechecking smears by a highly qualified observer. To evaluate and highlight the importance of quality control of smear microscopy in the Provincial Laboratories diagnosticians of Tuberculosis in Cuba. This study was conducted at the National Reference Laboratory and Research in Tuberculosis, Leprosy and Mycobacteria in the Institute of Tropical Medicine "Pedro Kouri", Havana, Cuba, Were evaluated 2676 smears received from January 2013 to December 2014, from Provincial Centers of Hygiene, Epidemiology and Microbiology of Cuba, including the special municipality Isla de la Juventud. 2,664 (99.5%) were concordant smears, the correlation obtained for the positive smears were 96.5% and 99.8% for negative. Were identified12 reading errors: 7 (3.5%) false positive and 5 (0.2%) false negatives. Slides were classified with adequate quality of smears in 2039 (76.2%), showed difficulties in realizing the extension in 1464 (54.7%) and staining were adequate in 2343 (87.6%). The kappa index was 0.9674. Although there was good agreement between observations it is recommended to improve the quality of extended, maintain staff training program that performs this activity, like regular supervision by specialists, to further improve the quality of diagnosis.