Ohrt Colin, Obare Peter, Nanakorn Ampon, Adhiambo Christine, Awuondo Ken, O'Meara Wendy Prudhomme, Remich Shon, Martin Kurt, Cook Earnest, Chretien Jean-Paul, Lucas Carmen, Osoga Joseph, McEvoy Peter, Owaga Martin Lucas, Odera James Sande, Ogutu Bernhards
Walter Reed Army Institute of Research, Silver Spring, Maryland, USA.
Malar J. 2007 Jun 12;6:79. doi: 10.1186/1475-2875-6-79.
Malaria microscopy, while the gold standard for malaria diagnosis, has limitations. Efficacy estimates in drug and vaccine malaria trials are very sensitive to small errors in microscopy endpoints. This fact led to the establishment of a Malaria Diagnostics Centre of Excellence in Kisumu, Kenya. The primary objective was to ensure valid clinical trial and diagnostic test evaluations. Key secondary objectives were technology transfer to host countries, establishment of partnerships, and training of clinical microscopists.
A twelve-day "long" and a four-day "short" training course consisting of supervised laboratory practicals, lectures, group discussions, demonstrations, and take home assignments were developed. Well characterized slides were developed and training materials iteratively improved. Objective pre- and post-course evaluations consisted of 30 slides (19 negative, 11 positive) with a density range of 50-660 parasites/mul, a written examination (65 questions), a photographic image examination (30 images of artifacts and species specific characteristics), and a parasite counting examination.
To date, 209 microscopists have participated from 11 countries. Seventy-seven experienced microscopists participated in the "long" courses, including 47 research microscopists. Sensitivity improved by a mean of 14% (CI 9-19%) from 77% baseline (CI 73-81 %), while specificity improved by a mean of 17% (CI 11-23%) from 76% (CI 70-82%) baseline. Twenty-three microscopists who had been selected for a four-day refresher course showed continued improvement with a mean final sensitivity of 95% (CI 91-98%) and specificity of 97% (CI 95-100%). Only 9% of those taking the pre-test in the "long" course achieved a 90% sensitivity and 95% specificity, which increased to 61% of those completing the "short" course. All measures of performance improved substantially across each of the five organization types and in each course offered.
The data clearly illustrated that false positive and negative malaria smears are a serious problem, even with research microscopists. Training dramatically improved performance. Quality microscopy can be provided by the Centre of Excellence concept. This concept can be extended to other diagnostics of public health importance, and comprehensive disease control strategies.
疟疾显微镜检查虽是疟疾诊断的金标准，但存在局限性。药物和疫苗疟疾试验中的疗效评估对显微镜检查终点的小误差非常敏感。这一事实促使在肯尼亚基苏木建立了一个卓越疟疾诊断中心。主要目标是确保有效的临床试验和诊断测试评估。关键的次要目标是向主办国进行技术转让、建立伙伴关系以及培训临床显微镜检查人员。
开发了一个为期12天的“长期”和一个为期4天的“短期”培训课程，包括有监督的实验室实践、讲座、小组讨论、示范以及课后作业。制作了特征明确的载玻片，并对培训材料进行了反复改进。客观的课前和课后评估包括30张载玻片（19张阴性，11张阳性），寄生虫密度范围为50 - 660个/微升，一次书面考试（65道题），一次摄影图像考试（30张伪像和物种特异性特征的图像）以及一次寄生虫计数考试。
迄今为止，来自11个国家的209名显微镜检查人员参加了培训。77名经验丰富的显微镜检查人员参加了“长期”课程，其中包括47名研究显微镜检查人员。敏感性从基线的77%（置信区间73 - 81%）平均提高了14%（置信区间9 - 19%），而特异性从基线的76%（置信区间70 - 82%）平均提高了17%（置信区间11 - 23%）。被选参加为期4天复习课程的23名显微镜检查人员持续进步，最终平均敏感性为95%（置信区间91 - 98%），特异性为97%（置信区间95 - 100%）。在“长期”课程中进行预测试的人员中，只有9%达到了90%的敏感性和95%的特异性，而在完成“短期”课程的人员中这一比例增至61%。在提供的每门课程中，五种组织类型中的每一种的所有性能指标都有显著提高。
数据清楚地表明，即使是研究显微镜检查人员，疟疾涂片的假阳性和假阴性也是一个严重问题。培训显著提高了性能。卓越中心的理念可以提供高质量的显微镜检查。这一理念可以扩展到其他具有公共卫生重要性的诊断以及全面的疾病控制策略。
