The highest sensitivity across STH species was observed for the FLOTAC method in both high and low infection intensity settings. Kato-Katz performed reasonably well in high infection intensity settings.
A paper published in the October issue of the International Journal for Parasitology presented findings from a meta-analysis comparing the sensitivities and quantitative performance of the most commonly used diagnostic methods for soil-transmitted helminths (STH): Kato-Katz, direct microscopy, formol-ether concentration, McMaster, FLOTAC and Mini-FLOTAC.
The choice of diagnostic method used to detect infection needs to be adapted to the setting of the survey, both in terms of transmission intensity and practical feasbility. The article aims to provide a robust global assessment of the relative performance of available diagnostic tools for the detection of STH. By stratifying the analysis according to intensity of infection, the suitability of tests in different settings was examined. Analysis was species specific and tested each diagnostic method for Ascaris lumbricoides, Trichuris trichiura and the hookworms.
Overall, authors founds that sensitivity estimates varied between the different methods, ranging from 42.8% for direct microscopy to 92.7% for FLOTAC. The Kato-Katz method had a sensitivity of 74–95% for the three STH species at high infection intensity. However, sensitivity dropped to 53–80% in low intensity settings, being lowest for hookworm and A. lumbricoides. The highest sensitivity, overall and in both intensity groups, was observed for the FLOTAC method.
First author, Birgit Nikolay, says, "The analysis was a first attempt to assess the different test performances based on available data. More detailed studies comparing the various diagnostic tests in different settings under standardised conditions are needed to obtain better sensitivity estimates."
Authors:
Birgit Nikolay
Rachel Pullan
Simon Brooker
All from GAHI, based at the London School of Hygiene & Tropical Medicine
The paper is available in our Publications and from The International Journal for Parasitology via ScienceDirect.
Read more about STH control and our work in diagnostics.
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