autohaem: 3D printed devices for automated preparation of blood smears

TL;DR

This paper introduces open-source 3D printed devices for automated blood smear preparation, aiming to enhance consistency, throughput, and quality in malaria research and diagnostics.

Contribution

It provides fully documented, easily fabricated devices and an image analysis pipeline to optimize and standardize blood smear preparation.

Findings

Devices match expert human performance

Automation improves reproducibility and standardization

Open-source designs facilitate local manufacturing

Abstract

The process of making blood smears is common in both research and clinical settings, for investigating the health of blood cells and the presence of blood-borne parasites. It is very often carried out manually. We focus here on smears for malaria diagnosis and research which are frequently analyzed by optical microscopy and require a high quality. Automating the smear preparation promises to increase throughput and to improve the quality and consistency of the smears. We present here two devices (manual and motorized) designed to aid in the making of blood smears. These are fully documented, open-source hardware, and an important principle was to make them easily fabricated locally anywhere. Designs and assembly instructions are freely available under an open license. We also describe an image analysis pipeline for characterizing the quality of smears, and use it to optimize the settings and tunable parameters in the two devices. The devices perform as well as expert human operators, while not requiring a trained operator and offering potential advantages in reproducibility and standardization across facilities.