Investigation of a visual colour-change test for detecting SARS-CoV-2 infection in patient samples

Study code

Lead researcher
Professor Anne E Willis

Study type
Participant re-contact

Institution or company
MRC Toxicology Unit

Researcher type

Speciality area
Infection, COVID

Recruitment Site


SARS-CoV-2 is the virus that causes COVID-19.  There is an urgent need to develop tests that accurately detect whether a patient is infected with SARS-CoV-2 as soon as possible to detect further spread of this global pandemic. For this reason, we are developing a test that a patient could perform at home. Unlike other tests for SARS-CoV-2 such as lateral flow tests, this test detects viral enzymes which are produced at an earlier stage of infection and may help to identify infected patients sooner and before they are able to transmit the virus to others. 

The test requires a patient to provide a sample of saliva and/or a swab of the nose and/or throat.  This is then added to the reaction solution and left at room temperature for 30-90 minutes.  The reaction solution is then mixed with the developing solution which is a red colour.  If a patient is not infected with the virus then their test will remain red.  However, if a patient is infected with SARS-CoV-2 then their test will immediately turn blue.

Therefore, we need patient samples of known infection status for SARS-CoV-2 (as determined by the PCR test) to provide fresh samples of saliva and swabs of the nose and throat.  We will then perform our test to detect the SARS-CoV-2 viral enzymes and assess how accurately and sensitively this test detects SARS-CoV-2 infection status.  If successful, we will develop this test further so that it can be used in the public setting as a diagnostic test for COVID-19.

Participation: For this study, 5 participants from the COVID-19 BioResource participated by providing a saliva sample and conducting a nasal swab.

Organisation: This study is organised by Professor Anne E Willis OBE at the MRC Toxicology Unit, Cambridge