Stool-based testing method: A revolutionary, convenient, accurate and pain-free approach to diagnose childhood tuberculosis

In a recent study, conducted by the Ethiopian Public Health Institute (EPHI), KNCV Tuberculosis Foundation and others, rigorously evaluated the diagnostic accuracy, feasibility, and acceptability of stool-based testing for childhood tuberculosis (TB). Especially in children, stool-based testing can be an alternative to the usual, complex, invasive, stressful, and sometimes painful method for diagnosing TB. Stool-based testing for TB has been recommended by the World Health Organization (WHO) since 2021, and KNCV has previously developed the Simple One-Step (SOS) stool-method with Xpert MTB/RIF Ultra (Xpert-Ultra) for childhood TB diagnosis.  

The study, led by Bazezew Yenew, research associate at EPHI, and Petra de Haas, laboratory advisor at KNCV and innovator of the aforementioned SOS stool-method test, compares the SOS stool-method to traditional methods of TB testing, such as culture, clinical diagnosis, and Xpert-Ultra on respiratory samples (RS), also known as sputum. Adults are able to cough up sputum, which then can be examined for TB. However, for small children who are not able to cough up sputum, an invasive and painful procedure is required to retrieve a sample containing the swallowed sputum from the stomach. With the SOS stool-method, this can be retrieved and studied from a stool sample.  

Study findings 

The study included 898 children with presumptive pulmonary TB, and the diagnostic accuracy of the SOS stool-method with Xpert-Ultra was compared against culture, Xpert-Ultra on respiratory samples, and clinical diagnosis. The sensitivity estimates for stool-based testing ranged from 59.0% to 76.8%, with specificity exceeding 98.8% for all comparisons. These results demonstrate the effectiveness of stool-based testing as a viable alternative to traditional methods for TB diagnosis in children. 

On top of that, the study showcases the feasibility and acceptability of stool testing among laboratory staff and caregivers. Laboratory staff found stool collection feasible and the SOS stool-method easy to perform. Notably, a significant majority of caregivers (75%) expressed a preference for stool-based TB diagnosis over other standard RS testing. 


The study shows that SOS stool Xpert-Ultra testing offers a good alternative to RS testing for TB in children who cannot spontaneously produce a sputum sample and would otherwise need to undergo invasive procedures to obtain RS for diagnosis, providing both the children and the healthcare workers with an accurate, easy, less stressful, and pain-free way that leads to the right diagnosis. 

Click here to read the study, or here to view more recent publications by KNCV 

KNCV has been fighting TB since its establishment in 1903. Over the past 120 years, the organization has acquired indispensable knowledge and experience in the field of effective TB prevention and care, resulting in pre-elimination in the Netherlands and significant contributions to global evidence generation, policy development and TB program implementation worldwide.

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