15.09.2020 By Medusa19


The Rapid Saliva Protein Test (“RSPT”), from Medusa 19, provides results on the spot in 10 minutes. It is a lateral flow saliva test to indicate the immune response to infection particularly in patients who do not know they have an active SARS-CoV-2 infection and have no specific symptoms.

The 10-minute result window for a saliva immune response is a significant breakthrough for the COVID-19 testing market. The RSPT is point-of-care, providing rapid results on the spot.

The non-invasive test requires simple saliva collection, and is less intrusive than a blood sample, nasal or throat swab. Developed in the UK and Spain, the test indicates a user’s immune response to SARS-CoV-2, the virus underlying COVID-19.

Users provide a saliva sample into a collection tube, mixing this with a solution, which isolates and solubilises the protein structure present in saliva. This mixture is applied to a lateral flow device which migrates the saliva sample along the device. The test identifies antibodies unique to COVID-19, capturing them on test and control lines.

The RSPT isolates the protein complexes in saliva, allowing for recognition of saliva antibodies produced after the first contact with the virus, immunoglobulin M (IgM) and immunoglobulin G (IgG).  Antibodies are produced when a virus is present as part of the body’s immune system response to infection.

At the early stage of infection, human cells produce an immune response and generate IgG, but more specifically IgM at the point of contact with the virus, which for COVID-19 is in the throat and respiratory tract.  The antibodies are then transported from the lymph nodes into blood and saliva. In the early stage, detection in blood is not sensitive enough due to a high dilution effect, whereas in saliva, the independent clinical data indicates it is detectable.

Importantly, since this test indicates an immune response to current or recent infection, it can therefore alert users if they should immediately self-isolate to stop the spread of the disease.  Independent clinical trials were conducted in collaboration with Hospital Carlos III/Institute Carlos III – Hospital La PAZ, Madrid, on 254 participants.  In a cohort of patients with no specific symptoms, the trial demonstrated relative sensitivity of 96 per cent (ability to detect true positives), relative specificity of 92 per cent (ability to detect true negatives) and 94 per cent accuracy in patients with the absence of specific symptoms and who did not know they had an active SARS-CoV-2 infection.

The test is CE marked to 98/79/EC, registered with the MHRA, and is for use under supervision from a medical professional throughout Europe.  It could prove pivotal in helping companies safely reopen workplaces and take action in line with government guidance.  The RSPT is under application with the FDA Emergency Use Authorisation for approval in the USA.

Medusa 19 is currently working to develop an app which will act as a digital passport to verify and validate RSPT results, the Saturn Pass.

Christian Stephenson, Chief Development Officer at Medusa 19, commented: “Testing for infection is pivotal to navigating the pandemic. The clinical evaluation showed the detection of an immune response to the virus could be detected in patients with no specific symptoms rapidly and accurately from a saliva sample which is a game-changer. By testing on a mass scale, outbreaks can be quickly pin-pointed and brought under control, therefore avoiding the imposition of strict blanket lockdowns.

“The ability to rapidly test on a mass scale represents a huge leap forward for the global recovery from COVID-19, pioneered here in the UK. Clinical trial results are encouraging, and this could provide the global workforce with an accessible, reliable test, that can indicate an immune response to current or recent infection, even in carriers with no specific symptoms. It could be a lifeline for businesses struggling to safely reopen, and we are working tirelessly to seek approval for use for the general public too.”

Andy White, Managing Director of Medusa 19, added: “Development of the RSPT focused on providing end users with a highly accurate result quickly via a simple and non-invasive sampling process utilising saliva, with a test that had the potential to be manufactured globally and distributed worldwide. The Medusa 19 team has worked with extraordinary dedication to produce this unique test in a matter of months, alongside the necessary infrastructure and fulfilment capability and we are delighted with the clinical results.

“Global demand for a reliable and rapid test of this nature is expected to be in the billions of tests per annum, and therefore it is important that we are able to manufacture and distribute this test widely, both at home and overseas. The infrastructure behind the test means it can be produced on mass, and by investing in a wide roll-out of this unique test, businesses can take a vital step forward in getting back to work safely, in line with government guidance.”


Medusa 19 is also exploring a number of other complementary tests and diagnostic products, and earlier this year entered an exclusive distribution agreement with Avacta Group plc for direct-to-consumer sales of a saliva-based antigen test. It will utilise its infrastructure to distribute this product worldwide once available.

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