Here, we described the establishment and impact of a training program in malaria microscopy that was implemented at four districts in Uganda to build local capacity and improve test accuracy. A total of 192 personnel capable of performing malaria microscopy were identified in four districts, which have a combined population of over 1 million people, resulting in approximately 1 microscopist for every 5,000 residents. These numbers highlight the severe lack of laboratory capacity in Uganda given that the incidence of malaria has been estimated to be 478 cases per 1,000 persons per year.9
Most of the laboratory personnel were low-level cadres (microscopists or laboratory assistants) who came from upper-level health facilities and hospitals, characteristics that have been described in other African countries.4
Training led to an improvement in didactic test scores, reflecting an increase in knowledge of key concepts and facts about malaria microscopy. However, documenting increases in knowledge is not the same as documenting improvements in performance.
One of the strengths in the evaluation of this training program was the comparison of diagnostic accuracy before and after training under real world conditions. It is well-recognized that blood-smear readings are highly dependent on the level of experience of the microscopist, techniques used to prepare and stain the blood slide, and quality control standards.10–12
The diagnostic accuracy of field microscopy was surprisingly good before the training program, with an overall sensitivity of 84% and specificity of 87%. However, these findings may have been influenced by the fact that personnel were aware that slides were being collected for evaluation purpose. A high sensitivity is especially important clinically because of the risk of not treating a true case of malaria. A high specificity is important for reducing the use of unnecessary antimalarials and prompting clinicians to look for alternative causes of illness. After training, diagnostic accuracy improved significantly and consistently across most of the health facilities evaluated. Indeed, the post-training sensitivity and specificity of 95% and 97%, respectively, were excellent and higher than have been reported in other malaria diagnostic training programs from Africa.5–7
A similar level of diagnostic accuracy was achieved in Kisumu, Kenya, where a malaria diagnostic center of excellence has been established, providing an intensive long course followed by short-course refresher training.13
One of the main objectives of the training was to improve malaria blood-slide preparation techniques. Indeed, improvement in malaria blood-slide preparation is the first step to improvement in the accuracy of reading malaria blood slides. The poor quality of blood-smear preparation before this training program was dramatically improved after training, with the proportion of well-prepared slides increasing on average from 6% to 75%. In practice, microscopy varies a great deal in different settings because of variable techniques of blood-film preparation, staining, malaria film-reading standards, and level of expertise of the examining microscopists.10,11
Poor blood-film preparation can lead to false-positive results because of the presence of artefacts commonly mistaken for malaria parasites or false-negative results because of inadequate staining, and it increases the time and effort that it takes to read a blood smear.14
The preparation of high-quality blood slides not only requires proper training but also the provision of essential supplies (clean slides, good stain, proper buffer, etc.) and a quality control system to ensure that proper procedures are being followed.
Potential benefits of parasite-based diagnosis depend on accurate results and the proper use of these results in patient management. A prompt and accurate diagnosis is critical for guiding rationale therapeutic decision making for both malaria and non-malaria illnesses.15
Most malaria-endemic countries have now adopted the use of highly effective but expensive ACT for the treatment of malaria.1
Restricted and better directed treatment of malaria is increasingly being advocated to prevent the unnecessary use of ACTs and hence, reduce drug pressure selecting for resistant parasites and frequency of potential adverse drug reactions.16,17
A lack of confidence in accuracy has been cited as a common reason for clinicians ignoring test results, which most commonly manifests in the practice of prescribing antimalarials to patients with negative blood smears.18,19
Improving and documenting the accuracy of microscopy under field conditions is critical for instilling confidence in clinicians so that they can make rational decisions when prescribing antimalarials.
In summary, requirements for laboratory services are growing in malaria-endemic countries where there is a move away from empiric therapy and to parasitological confirmation of the diagnosis. In Uganda, there is a shortage of laboratory personnel, and the quality assurance system is not fully functional. The District Directorate of Health is responsible for maintaining quality laboratory services with national support from the Central Public Health Laboratory. The program described here shows that supplemental training can have a significant impact on the accuracy of malaria microscopy and achieve excellent results in the short term. Efforts are currently underway to expand this refresher training program around the country, and continued supervision and support are essential to ensure sustainability of accurate diagnosis and thereby, appropriate treatment of malaria. These findings should be interpreted in light of the fact that evaluation closely followed training. A long-term monitoring of performance is essential to recommend the appropriate frequency of refresher training.