Martinez-Guarneros A, Balandrano-Campos S, Solano-Ceh M A, Gonzalez-Dominguez F, Lipman H B, Ridderhof J C, Flisser A
Department of Mycobacteria, InDRE, Mexico, DF, Mexico.
Int J Tuberc Lung Dis. 2003 Jun;7(6):516-21.
In developing countries, tuberculosis is diagnosed by identification of acid-fast bacilli (AFB) on sputum smears.
To evaluate the quality of AFB microscopy, the Mexican Secretary of Health National Reference Laboratory implemented proficiency testing for its network of 637 laboratories.
A total of 586 (92%) laboratories were inspected and 430 technicians evaluated by proficiency testing consisting of 10 slides with known numbers of AFB. Results were compared with those of slide rechecking and with proficiency testing performed 2 years later.
Of the 430 technicians evaluated by proficiency testing in 1998, 196 (46%) scored less than 80% and received intensive training in 1999. From a previous mean score of 65% their results increased to 90% (P < 0.0001). In 2001, they again underwent proficiency testing, and the mean score was 83%. The main factors affecting proficiency testing results were the type of laboratory in which the microscopists worked and the number of low-positive slides (1-9/100) in the test. Laboratories whose work was rechecked had better scores (P = 0.002). Proficiency testing scores and the estimated sensitivity of the microscopist's laboratory were associated (P = 0.01).
External quality assessment and training improve diagnostic performance. Rechecking and proficiency testing are both viable measures of laboratory performance.
在发展中国家，结核病通过痰涂片上抗酸杆菌（AFB）的鉴定来诊断。
为评估AFB显微镜检查的质量，墨西哥卫生部国家参考实验室对其637家实验室网络进行了能力验证测试。
共检查了586家（92%）实验室，并通过由10张载有已知数量AFB的玻片组成的能力验证测试对430名技术人员进行了评估。将结果与玻片复查结果以及2年后进行的能力验证测试结果进行比较。
在1998年通过能力验证测试评估的430名技术人员中，196名（46%）得分低于80%，并于1999年接受了强化培训。他们的结果从之前的平均65%提高到了90%（P<0.0001）。2001年，他们再次接受能力验证测试，平均得分为83%。影响能力验证测试结果的主要因素是显微镜检查人员所在的实验室类型以及测试中低阳性玻片（1 - 9/100）的数量。其工作被复查的实验室得分更高（P = 0.002）。能力验证测试得分与显微镜检查人员所在实验室的估计灵敏度相关（P = 0.01）。
外部质量评估和培训可提高诊断性能。复查和能力验证测试都是评估实验室性能的可行措施。
