Operational Experience of a Quality Assurance System for HPV DNA Chip Tests / 임상검사와정도관리

BACKGROUND: A new HPV DNA chip test for the infection of 22 HPV genotypes was recently developed in Korea. This test using PCR and hybridization is inherently vulnerable to contamination, and to subjective qualitative test judgment. Hence, it warrants rigorous quality assurance measures. The authors would like to share operational experiences of the guidelines developed at Catholic University Holy Family Hospital. METHODS: Our quality assurance system of HPV DNA chip test comprised external quality controls, inter-laboratory proficiency tests, and internal quality controls. For the external quality controls, we analyzed the results of four years of participation in the quality assurance program by the Korean Laboratory Medicine Quality Assurance Association. The inter-laboratory proficiency tests with BioMedLab were done by single blind tests using patients' samples showing negative, single and multiple infections. The internal quality control dealt with methods to prevent contamination, and with reproduction tests. RESULTS: The results from the external quality control revealed consistency with HPV-16 in 7 trials during 4 years. The inter-laboratory proficiency tests showed a 82% consistency rate, 10 cases of inconsistency showing positive or negative mismatches, and 8 cases of genotypic mismatches. The 10 mismatches were due to the weak laser power of the scanner used in BioMedLab. The genotypic contamination rate found in the internal quality control was 3.3%, and the contamination by HPV-35 with low incidence rate was often observed. The contamination was not easily eliminated by re-tests from hybridization, but 80% of it was removed when re-tested with the remaining samples. The fluorescence intensity was not reproducible nor provide quantitative or semi-quantitative information. CONCLUSIONS: For quality assurance regarding HPV DNA chip tests, we suggest the following be implemented: technical quality control to rule out the false-negative and false-positive during PCR and hybridization; scanner quality control to prevent reading errors; and inter-laboratory proficiency tests.

Resultados del programa nacional de estandarización en las determinaciones de lípidos en Costa Rica 1999-2000 / Results of the national programs of standarization in the lipid determinations in Costa Rica

Este programa lo inició el "Consejo para el Mejoramiento de la Calidad en Lípidos" en Costa Rica en 1999, realizando ocho encuestas en un período de dos años. Se distribuyó muestras de suero congelado manteniendo una red de frío durante el proceso. Se empleó como laboratorio de referencia el "Pacific Biometrics" en Seatle, acreditado por el "Center of Disease Control and Prevention" en Atlanta. Inicialmente participaron 43 laboratorios, aumentando gradualmente el número a 90 a finales del año 2000 con un porcentaje de respuesta promedio del 93 por ciento. El programa incorporó al 37 por ciento de los laboratorios clínicos del sector público y 14 por ciento del sector privado. Los coeficientes de variación promedio interlaboratorio para colesterol, triglicéridos y HDL-colesterol fueron de 8,4 ± 2,0; 12,6 ± 3,1; 24,2 ± 8,1, respectivamente. Los criterios del National Cholesterol Education Program en Estados unidos determinan que la variación máxima recomendada es de 9 por ciento, 15 por cientos y 22 por ciento para colesterol respectivamente, según lo cual el porcentaje promedio de laboratorios con resultados aceptables fue de 68 por ciento en colesterol, 74 por ciento en triglicéridos y 63 por ciento en HDL-colesterol.

The board for the improvement of the Quality in Lípidos" started this program in Costa Rica in 1999, carrying out eight surveys in a period of two year. Samples of frozen serum were distributed maintaining a net of cold during the process. The "Pacific Biometrics" in Seattle was used as reference laboratory, credited by the "Center of Disease Control and Prevention in Atlanta." Initially, 43 laboratories participated, increasing the number gradually to 90 at the end of the year 2000 with an average answering rate of 93%. The program incorporated 37% of the national clinical laboratories that correspond to 92% of the clinical laboratories of the public sector and 14% of the private sector. The average interlaboratory variation coefficients for cholesterol, triglycerides and HDL-cholesterol were of 8,4 ± 2,0; 12,6 ± 3,1; 24,2 ± 8,1, respectively. The approaches of the National Cholesterol Education Program in United States determine that the recommended maximum variation is 9%, 15% and 22% for cholesterol, triglycerides and HDL-cholesterol, respectively. According to this criteria, the average percentage of laboratories with acceptable results was of 68% for cholesterol, 74% for triglicéridos and 63% for HDL-cholesterol.