임상미생물검사 신빙도 조사 결과보고(1995)

Abstract

Two trials of external quality assessment for Clinical Microbiology were performed in 1995. A total of nine specimens were distributed. All except three specimens contained pure cultures of single bacterial pathogens ; two contained single pathogen and two commensals of enteric origin ; one contained two pathogens. Four specimens containing five pathogens were distributed to 265 laboratories with 167 returns(63.0%) in Trial I and five specimens to 224 laboratories with 181 returns(74.2%) in trial II. The percentage of fully correct results for identification of pathogens ranged from 99.4% for Escherichia coli to 54.4% for Nacardia asteroides with an average of 82.4% compared with 75.3% in 1994(P<0.001). The success rate of isolation and Citrobacter freundii in the mixed culture was 62.7% compared with 62.7% compared with 54.3% in 1992 when a specimen from a similarly mixed infection was used for assessment, but the difference was not statistically significant. Many of the errors made in species identification were repetitions of those made in previous year : failure to perform very basic tests such as oxidase, catalase and coagulase tests correctly. As was expected, the laboratories in tertiary care hospitals performed significantly between than other laboratories(P<0.05). The results of antimicrobial susceptibility testing were generally acceptable except for a few antimicrobials. However, disagreement was noted, as in the last year, between reported zone sizes and their interpretation by several laboratories, suggesting that the zone size interpretative standards of NCCLS might not be available to everyone. The external quality assessment program should be continued with an increasing participation of clinical laboratories to improve the quality of diagnostic microbiology in Korea.