ABSTRACT
Improvements in digital microscopy are critical for the development of a malaria diagnosis method that is accurate at the cellular level and exhibits satisfactory clinical performance. Digital microscopy can be enhanced by improving deep learning algorithms and achieving consistent staining results. In this study, a novel miLab™ device incorporating the solid hydrogel staining method was proposed for consistent blood film preparation, eliminating the use of complex equipment and liquid reagent maintenance. The miLab™ ensures consistent, high-quality, and reproducible blood films across various hematocrits by leveraging deformable staining patches. Embedded-deep-learning-enabled miLab™ was utilized to detect and classify malarial parasites from autofocused images of stained blood cells using an internal optical system. The results of this method were consistent with manual microscopy images. This method not only minimizes human error but also facilitates remote assistance and review by experts through digital image transmission. This method can set a new paradigm for on-site malaria diagnosis. The miLab™ algorithm for malaria detection achieved a total accuracy of 98.86% for infected red blood cell (RBC) classification. Clinical validation performed in Malawi demonstrated an overall percent agreement of 92.21%. Based on these results, miLab™ can become a reliable and efficient tool for decentralized malaria diagnosis.
ABSTRACT
An accurate microscopical analysis of blood smears requires a reproducible and convenient method of staining. Solution-based staining procedures can be cumbersome. Especially in low- and middle-income countries, the lack of skilled technicians and adequate laboratory facilities, as well as insufficient water and reagent quality, often become confounding factors. To overcome these obstacles, we developed a new cell staining method based on sequential stamping of agarose gel patches that contain eosin, methylene blue/oxidized methylene blue, Azure B, and buffer, respectively. Our method, termed "hydrogel staining", provides a simple, reproducible, solution-free, and inexpensive approach to stain blood cells. We have optimized incubation times to achieve the optimal transfer of dyes to fixed blood cells on a glass slide, with outcomes comparable to conventional solution-based methods for white blood cells and malaria-infected red blood cells. This hydrogel staining method does not require special skills to produce excellent quality stained blood film slides. The new method could enhance the accuracy of microscopical examination of blood smears, especially in resource-limited settings.
