The concentration McMaster method for diagnosis of patent Ascaris and Trichuris infections in humans

In tropical and subtropical regions, soil-transmitted helminth (STH) infections such as Ascaris lumbricoides, Trichuris trichiura, and hookworms have a significant impact on public health. Globally, A. lumbricoides infects approximately 0.8 billion people, while T. trichiura infects around 500 million. This study involved a comparison of three diagnostic methods, Kato-Katz and two flotation methods (concentration McMaster, and simple McMaster), for the detection of Ascaris and Trichuris in human faeces. We conducted a comparison of the number of eggs in faeces (or faecal egg counts (FECs)) obtained with these methods using freshly collected samples that were positive for T. trichiura and spiked with a known quantity of Ascaris sp. eggs. Additionally, for the concentration McMaster method we assessed FECs after storing the samples at 5 °C for up to 21 days. The concentration McMaster method demonstrated superiority over the simple McMaster method in terms of higher detection levels for both helminths, while the Kato-Katz method yielded FEC values very close to the 'true' spiking values. Importantly, the concentration McMaster method was considerably easier to read compared with the Kato-Katz method, and it allowed for sample storage at 5 °C for up to 14 days without affecting FEC results. Consequently, we conclude that the concentration McMaster method is an effective and user-friendly alternative for diagnosis of Ascaris and Trichuris infections in humans. Furthermore, it offers the advantage of sample storage before analysis, enhancing flexibility in the workflow.