Fink N E, Fernández Alberti A, Mazziotta D
Universidad Nacional de La Plata, Argentina.
Rev Panam Salud Publica. 1997 Sep;2(3):181-8.
The assurance of analytical quality in a clinical laboratory is achieved through an internal system of quality control complemented by an external evaluation program. Quality assurance provides a foundation for the confidence that is placed in laboratory results and their use in the diagnosis and treatment of diseases. Many laboratories in Latin American countries do not have appropriate systems in place to evaluate and control quality. Given the importance of diagnoses based on hematologic data, the Pan American Health Organization sponsored a course in quality control in hematology during the XI Latin American Congress of Clinical Biochemistry (Mexico, 1993), in which representatives from Argentina, Chile, Cuba, Mexico, Paraguay, Dominican Republic, and Uruguay participated. As part of the course, the following control materials were produced: secondary standard solution of cyanmethemoglobin, stabilized concentrated hemoglobin solution, and preserved human whole blood with pseudoleukocytes. These materials were sent to laboratories in the seven participating countries for use in analytical procedures, and the results were then subjected to an external evaluation to assess individual performance and the comparability of results among the group. The specific tasks carried out were: (1) determination of values for hemoglobin, hematocrit, and red and white blood cell counts by the procedures normally used in each laboratory; (2) recording of the data on special reporting forms; and (3) transmittal of those forms to the coordinator in each country. The results were analyzed with regard to both the procedure used and the participating country. Reference values were established by consensus following application of a statistical method to eliminate outlying values. Comparative analysis of the results showed the coefficients of variation (CV) of the hematocrit (4.5%), red blood cell count (11.0%), and white blood cell count (22.2%) to be higher than those reported from the United States of America and Europe. With regard to analytical procedures, the manual methods yielded larger CV than the automated methods. When analysis of variance (ANOVA) was used on data broken down by country and by procedure, the only statistically significant result was for leukocyte count (P < 0.02). It was concluded that training in the preparation of quality control materials and the subsequent use of these materials in pilot surveys could provide a starting point for establishing continuous internal and external quality assessment systems in hematology. Such systems, together with continuing education for laboratory personnel and the availability of automated instrumentation, will lead to achievement of optimum laboratory quality.
临床实验室的分析质量保证是通过内部质量控制体系并辅以外部评估计划来实现的。质量保证为人们对实验室结果及其在疾病诊断和治疗中的应用所抱有的信心奠定了基础。拉丁美洲国家的许多实验室没有适当的系统来评估和控制质量。鉴于基于血液学数据进行诊断的重要性，泛美卫生组织在第十一届拉丁美洲临床生物化学大会（墨西哥，1993年）期间主办了一期血液学质量控制课程，阿根廷、智利、古巴、墨西哥、巴拉圭、多米尼加共和国和乌拉圭的代表参加了该课程。作为课程的一部分，制作了以下控制材料：氰化高铁血红蛋白二级标准溶液、稳定化浓缩血红蛋白溶液以及含有假白细胞的保存人全血。这些材料被送往七个参与国的实验室用于分析程序，然后对结果进行外部评估，以评估个体表现以及该组内结果的可比性。所开展的具体任务包括：（1）通过每个实验室通常使用的程序测定血红蛋白、血细胞比容以及红细胞和白细胞计数的值；（2）将数据记录在特殊报告表格上；（3）将这些表格转交给每个国家的协调员。针对所使用的程序和参与国对结果进行了分析。在应用统计方法剔除异常值之后，通过协商一致确定了参考值。结果的比较分析表明，血细胞比容（4.5%）、红细胞计数（11.0%）和白细胞计数（22.2%）的变异系数高于美国和欧洲所报告的数值。就分析程序而言，手工方法产生的变异系数比自动化方法更大。当对按国家和程序分类的数据进行方差分析（ANOVA）时，唯一具有统计学显著性的结果是白细胞计数（P < 0.02）。得出的结论是，质量控制材料制备方面的培训以及随后在试点调查中使用这些材料可为建立血液学持续内部和外部质量评估系统提供一个起点。这样的系统，连同对实验室人员的继续教育以及自动化仪器的可用性，将有助于实现最佳的实验室质量。
