To support the fight against the COVID-19 pandemic, from March 29, the Faculty of Medicine at The Chinese University of Hong Kong (CU Medicine) has offered to conduct, for free, stool tests for asymptomatic children coming to Hong Kong by air to screen for possible COVID-19.  The test currently employed by the Department of Health relies on collection of respiratory samples. The false negative rate of deep throat saliva test increases to over 40% with improper collection technique. Collection is particularly difficult in young children and infants. The potentially high false negative rate of the current test for children is therefore of great public health concern. The stool test that CU Medicine has developed is non-invasive, accurate and is potentially a better option for screening test for asymptomatic populations such as young children and infants. By conducting stool tests for children, CU Medicine aims to help identify asymptomatic children carrying the COVID-19 virus as early as possible in order to stop its spread through our community.

CU Medicine will work with the Department of Health of the HKSAR Government on this free stool test for COVID-19 screening.   Starting from March 29, the Government has started to distribute stool test kits to arriving children at Hong Kong International Airport in which specimen collection details are included.  In this first phase, we are screening young children and infants. CU Medicine will process the stool specimens in its laboratory and provide the results to the Government the next day when the stool specimens are received.  The Government will follow up on those cases with positive results.

Studies of CU Medicine have found that the virus was detectable in the stool samples of all patients, regardless of the degree of illness. 20-30% patients were still positive for the virus in their stool samples even though it was no longer found in respiratory tract samples.

First Phase of Stool Screening Test Targets Children and Infants

Professor Paul CHAN Kay Sheung, Chairman of the Department of Microbiology, CU Medicine remarked, “It is difficult to collect deep throat saliva from babies and children.  The deep throat saliva tests could carry a rather high false negative rate of over 40% if it is not collected properly. Infants and children who have been infected with COVID-19 can become silent carriers and spread the disease in the community.  Stool specimens are more convenient to collect in the paediatric population and can give more accurate results.  This makes our stool test a better option for COVID-19 screening in babies and children.”

Stool Test Helps Enhance Hong Kong’s Capacity to Test for COVID-19

Professor Francis KL CHAN, Dean of the Faculty of Medicine and Director of the Centre for Gut Microbiota Research at CUHK remarked, “Hong Kong is facing a critical situation in combating the COVID-19 pandemic and many of the confirmed cases in the past few days are people returning from overseas.  We offer free stool test for COVID-19 screening to returnees to Hong Kong and hope that this alternative tool could help identify possible COVID-19 who may be asymptomatic carriers.  As we shall process the stool specimens in CU Medicine laboratory, this stool screening test will ramp up the capacity of the HKSAR government to test for COVID-19.” 

For more details of the stool test, please visit the website at https://www.med.cuhk.edu.hk/covid-19/stool-test-for-covid-19-virus-screening