Enhancing the quality of field prepared malaria blood smears

Abstract

In this thesis, a new method towards enhancing the quality of field prepared malaria blood smears is developed through the use of a newly designed, innovative tool. Malaria is a life threatening febrile illness caused by parasites that are transmitted to people through bites of infected mosquitoes. If the symptoms are not treated within 24 hours, malaria can progress to severe illness, often leading to death. The golden standard of malaria diagnosis, microscopy, requires a high quality thick and thin blood smear. The smears enable distinction of the parasites and assessment of the infection rate. However, currently there is no standardized way to prepare these smears, leading to inconsistencies in quality.

The field context shows to be the context with the lowest smear quality output, due to difficulties and errors in the process. The high proportion of low quality smears lead to misdiagnosis, wrong treatment and indirectly to preventable fatalities. Estimates show that 25-50% of the smears prepared in this context is of poor quality. To get an understanding where this problem comes from, the most impactful errors on the smear quality have been mapped; uncontrolled variables in the preparation process, a lack of experienced medical staff, degradation of the smears during air drying and unavailability of proper and clean (local) resources and equipment.

The Malaria Blood Sampling System (MBSS) has been developed with the aim to increase the quality of field prepared blood smears, by reducing the impact on the quality that is caused by the human, environment and available resources. The MBSS is not just a newly developed device, it is a new system and a new approach to blood smear preparation. It provides a more precise, effective and efficient way of preparing blood smears in the field.

The MBSS makes blood smear preparation more accessible for inexperienced people, this tackles the current problem of the lack of experienced staff and reduces the human impact on the quality. The increased accessibility is achieved by eliminating two of four uncontrolled variables; angle and pressure. In addition, the MBSS minimizes the impact of the blood volume variable, leaving the movement speed the only human controlled variable in the process.
The environmental impact on the smear quality is reduced by eliminating the possibility of dust, ants, flies and other debris to settle on the smears. The ability to dry the slide inside the device enables protective air drying. This makes diagnosis easier and more efficient, by avoiding that unwanted particles colour the stain, which would lead to much noise, possible interpretation errors and misdiagnosis.

One of the key aspects towards preparation of high quality smears, is making use of high quality equipment. Since the MBSS includes a high quality glass slide and a capillary tube, the impact of the equipment on the smear quality is controlled and the quality of the smear can be guaranteed. These items are included in the MBBS package; they eliminate the risk of using non-sterile, unclean or contaminated equipment.

The MBSS has proven to deliver high quality thick and thin smears. Data from tests with experts and amateurs shows that the MBSS scores higher on all aspects compared to the convention smear preparation method. There is an increase in ease of preparation, ability of preparation by inexperienced people, presumed smear quality, quality consistency and time efficiency. The MBSS has potential to be a game changer that will guarantee consistent high quality smears in low-resource and low-expertise settings, such as the field. Deploying the MBSS in the malaria diagnosis ‘infrastructure and system’ will establish and ensure higher efficiency and accuracy in malaria diagnosis, leading to an increase in the amount of correct treatments and fatality reduction.