[Importance of quality control of baciloscopy in laboratories that perform diagnosis of tuberculosis]. / Importancia del control de la calidad de la baciloscopia en los laboratorios de diagnóstico de tuberculosis.

BACKGROUND: 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. AIM: To evaluate and highlight the importance of quality control of smear microscopy in the Provincial Laboratories diagnosticians of Tuberculosis in Cuba. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Importancia del control de la calidad de la baciloscopia en los laboratorios de diagnóstico de tuberculosis / Importance of quality control of baciloscopy in laboratories that perform diagnosis of tuberculosis

Introducción: La baciloscopia es la herramienta primaria en el diagnóstico de la tuberculosis (TBC) pulmonar activa, siendo esta la técnica más utilizada internacionalmente en la búsqueda de casos infecciosos. El control de calidad consiste en la relectura de las láminas por un observador altamente calificado. Objetivo: Evaluar y destacar la importancia del control de la calidad de la baciloscopia en los laboratorios provinciales encargados del diagnóstico de TBC en Cuba. Material y Métodos: Este estudio fue realizado en el Laboratorio Nacional de Referencia e Investigaciones de Tuberculosis, Lepra y Micobacterias del Instituto de Medicina Tropical "Pedro Kourí", La Habana, Cuba. Fueron evaluadas 2.676 láminas recibidas en el período de enero de 2013-diciembre de 2014, procedentes de los diferentes Centros Provinciales de Higiene, Epidemiología y Microbiología de Cuba, incluido el Municipio Especial Isla de la Juventud. Resultados: Hubo 2.664 (99,5%) láminas concordantes, la concordancia obtenida para las láminas positivas fue 96,5% y las negativas 99,8%. Se identificaron 12 errores de lectura: 7 (3,5%) falsos positivos, 5 (0,2%) falsos negativos. Se calificaron láminas con calidad de la muestra adecuada en 2.039 (76,2%), presentaron deficiencias en la realización de la extensión 1.464 (54,7%), y la tinción fue adecuada en 2.343 (87,6%). El índice de kappa fue de 0.9674. Conclusión: Aunque hubo una adecuada concordancia entre las observaciones realizadas, se recomienda mejorar la calidad del extendido, mantener programa de entrenamiento al personal que realiza esta actividad, al igual que las supervisiones periódicas por parte de especialistas, para continuar mejorando la calidad del diagnóstico.

Background: 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. Aim: To evaluate and highlight the importance of quality control of smear microscopy in the Provincial Laboratories diagnosticians of Tuberculosis in Cuba. Methods: 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. Results: 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. Conclusion: 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.