DIAGNOSTICS

Soil-transmitted helminthiasis (STH) is typically diagnosed through examination of patient stool samples using a microscope. A variety of examination tests are available to diagnose STH including Kato-Katz, formol-ether concentration, McMaster, FLOTAC, and Mini-FLOTAC. Of these, Kato-Katz and FLOTAC/Mini FLOTAC are most commonly used. New diagnostic methods using qPCR and PCR have also been developed, which allow laboratory technicians to efficiently test for multiple parasitic infections and, in the case of qPCR, quantify the intensity of infection with one sample. PCR diagnostics are especially important in that they are much more sensitive, thus improving detection of low intensity infections. 

KATO-KATZ

How it works: An individual is classified as either infected or uninfected for each helminth species through a fecal smear examined with a microscope. Intensity of infection for is measured in terms of eggs per gram (EPG) of feces. FIND OUT MORE!

Strengths: Most widely used approach, relatively easy to use for the laboratory technician, requires minimal equipment, reusable and inexpensive, laboratory technician can be trained within half a day to perform the test.

Weakness: Lack of sensitivity for detecting light-intensity STH infection (i.e. low EPG), accuracy dependent on the competency of the laboratory technician, clearing time of 20-40 minutes.

How to obtain Kato-Katz kits

WHO provides test kits to Ministry of Health-run national STH programs kits free-of-charge, when available.  

Because of the diligent efforts of the World Health Organization (WHO), Children Without Worms, and STH Coalition partners, there are now several vendors of high-quality Kato-Katz kits.

Combined Biotech Co., Ltd., China
Email: cbd@biocbd.com
Website: www.biocbd.com
Any size order will be filled.  A recent publication documents the comparability of the template for this test and the one manufactured by Vestergaard. Cost is $25 for 100 tests ($0.25/test).

Sterlitech Corporation, USA
Email: info@sterlitech.com
Website: www.sterlitech.com
Cost is $120 for 500 tests ($0.24/test).

*Note: Children Without Worms of the Task Force for Global Health shares the above information for informational purposes only. We have no relationship, financial or otherwise, with any named supplier. We do not endorse any particular supplier and The Task Force for Global Health assumes no responsibility or liability for any transactions entered into with or by the named suppliers.

 

FLOTAC/Mini-FLOTAC

How it works: Mini-FLOTAC is a diagnostic method based on flotation of helminth eggs. Mini-FLOTAC is part of the fill-FLOTAC kit, a device used to homogenize, filter, and pour the sample into flotation chambers. FIND OUT MORE!

Strength: Higher diagnostic sensitivity  of light-intensity infections.

Weakness: As compared to Kato-Katz, this procedure is more complicated and requires better equipped laboratories and more extensive training of laboratory technicians.

NEW DIAGNOSTICS

Accurate assessment of STH prevalence and intensity of infection are essential to plan and implement effective STH control. Molecular diagnostics, which identify parasite DNA in samples, are able to diagnose low intensity infections (i.e. low eggs per gram of stool), potentially reduce testing costs by pooling samples, and effectively test stored samples. Many different molecular platforms, in particular those based on polymerase chain reaction (PCR), are being field tested and refined for use by national programs. PCR diagnostic tests are currently being field tested in STH endemic areas of Ghana, Togo, Bangladesh, and in the Philippines.