Simşek Hülya, Ceyhan Ismail, Tarhan Gülnur, Güner Uğur
Refik Saydam Hıfzıssıhha Merkezi Başkanlığı, Ulusal Tüberküloz Referans ve Araştırma Laboratuvarı, Ankara, Türkiye.
Mikrobiyol Bul. 2010 Oct;44(4):561-9.
Recently, the diagnosis of pulmonary tuberculosis (TB) has based on smear microscopy in the Direct Observed Treatment Strategy (DOTS) programme which provides the basis of treatment worldwide. Microscopic detection of AFB (Acid-Fast Bacilli) is one of the main components in the National TB Control Programmes (NTCP). Precision level in microscopy procedures and evaluations are the most important steps for accurate diagnosis of the disease and to initiate proper treatment. Therefore, the external quality assessment (EQA) is the most important implement to provide the reliability and validity of tests. In countries where NTCP are performed, this task is fulfilled by the National Reference Laboratories (NRL) according to the guidelines of the World Health Organization (WHO). For this purpose a pilot study was initiated by the central NRL of Turkey for EQA of AFB smear microscopy as part of the NTCP on January 1, 2005. A total of 5 laboratories of which 2 were district TB laboratories (A, B), 2 were tuberculosis control dispensaries (C, D), 1 was a national reference laboratory (E), participated in this study. Blind re-checking method (re-examination of randomly selected slides) was used for the evaluation, and the slides were sent to the central NRL with 3 months interval, four times a year, selected according to LQAS (Lot Quality Assurance Sampling) guides. In the re-evaluation of the slides, false positivity (FP), false negativity (FN) and quantification errors (QE) were noted. Laboratory A, sent totally 525 slides between January 1, 2005 and April 1, 2008. In the result of re-checking, 514 (97.9%) slides were found concordant, and 11 (2.1%) were discordant (10 FP, 1 FN). Laboratory B, participated in the study between October 1, 2005 and July 1, 2006 and of the 67 re-examined slides, 60 (89.5%) were concordant and 7 (10.5%) were discordant (2 FP, 0 FN, 5 QE). Laboratory C, sent 235 slides between January 1, 2005 and April 1, 2006; of them 218 (92.8%) were detected as compatible and 17 (7.2%) slides were incompatible (4 FP, 9 FN, 4 QE). Laboratory D, participated in QC for only once between January 1, 2008 and April 1, 2008; and all the 50 slides were found compatible, with no FP, FN and QE. Laboratory E, was included in the study between January 1, 2005 and January 1, 2008 and of the 696 re-checked slides, 690 (99.1%) were reported as compatible and 6 (0.9%) were incompatible (3 FN, 3 QE). Following EQA, on-site evaluation of the laboratories with major errors, was performed and necessary adjustments and training were done. In conclusion, external quality control measures for AFB microscopy is crucial and essential for the tuberculosis laboratory performances for accurate and reliable results.
最近，在全球提供治疗依据的直接观察治疗策略（DOTS）项目中，肺结核（TB）的诊断基于涂片显微镜检查。抗酸杆菌（AFB）的显微镜检测是国家结核病控制规划（NTCP）的主要组成部分之一。显微镜检查程序和评估的精准度是准确诊断疾病并开始适当治疗的最重要步骤。因此，外部质量评估（EQA）是确保检测可靠性和有效性的最重要手段。在实施NTCP的国家，这项任务由国家参考实验室（NRL）根据世界卫生组织（WHO）的指南来完成。为此，土耳其中央NRL于2005年1月1日启动了一项关于AFB涂片显微镜检查EQA的试点研究，作为NTCP的一部分。共有5个实验室参与了这项研究，其中2个是地区结核病实验室（A、B），2个是结核病防治所（C、D），1个是国家参考实验室（E）。评估采用盲法重新检查方法（对随机选择的玻片进行重新检查），玻片按照批量质量保证抽样（LQAS）指南选择，每年分四次，每隔3个月送往中央NRL。在玻片的重新评估中，记录了假阳性（FP）、假阴性（FN）和定量误差（QE）。实验室A在2005年1月1日至2008年4月1日期间共送检了525张玻片。重新检查结果显示，514张（97.9%）玻片结果一致，11张（2.1%）不一致（10例假阳性，1例假阴性）。实验室B在2005年10月1日至2006年7月1日期间参与了研究，在67张重新检查的玻片中，60张（89.5%）结果一致，7张（10.5%）不一致（2例假阳性，0例假阴性，5例定量误差）。实验室C在2005年1月1日至2006年4月1日期间送检了235张玻片；其中218张（92.8%）检测结果相符，17张（7.2%）不相符（4例假阳性，9例假阴性，4例定量误差）。实验室D仅在2008年1月1日至2008年4月期间参与了一次质量控制；所有50张玻片结果均相符，无假阳性、假阴性和定量误差。实验室E在2005年1月1日至2008年1月1日期间参与了研究，在696张重新检查的玻片中，690张（99.1%）报告结果相符，6张（0.9%）不相符（3例假阴性，3例定量误差）。在EQA之后，对存在重大误差的实验室进行了现场评估，并进行了必要的调整和培训。总之，AFB显微镜检查的外部质量控制措施对于结核病实验室获得准确可靠的结果至关重要。
