How does the test cassette work?
The test is a lateral flow immunoassay test and operates in a similar way to a pregnancy test. Embedded into the test strip are antibodies that bind to a COVID-19 specific biomarker, Immunoglobulin G (IgG), and another infection biomarker, Immunoglobulin M (IgM). When a sample (blood, serum or plasma) is added to one end of the test, it flows along the test strip and interacts with these antibodies. If the patient has contracted COVID-19, the biomarkers in their blood will bind to the antibodies on the test strip, leaving a visible test line. If the patient doesn’t have COVID-19, no biomarkers should be present in their blood and no test line will be visible. There are separate test lines for IgG and IgM and only one needs to be visible for a positive result.
What are IgG and IgM?
Immunoglobulins are antibodies themselves and are part of our immune system. When we get an infection, such as COVID-19, immunoglobulins are produced, which attach to the virus and activate the rest of the immune system to attack and clear the virus. IgM is the first immunoglobulin to be produced. The presence of IgM is an indicator of early infection. The presence of IgG is an indicator of later stage infection (usually 7 days or longer after infection).
What samples can I use?
The test cassette will work with whole blood, plasma or serum. Capillary blood is the easiest to obtain via a finger pinprick, however, venous blood obtained via venepuncture is also suitable. The type of sample will not affect the sensitivity or accuracy of the test.
What is the buffer solution for and can I use any buffer with the test?
The buffer solution has two functions. It acts as the carrier for the sample, allowing it to laterally flow along the test strip, and it maintains a constant sample pH as it flows, preventing degradation of the biomarkers and the antibodies. We recommend that you only use the buffer solution provided with the test kits, as other ones may affect the accuracy of the test.
So can the test detect asymptomatic patients?
Yes, the test will be able to detect IgM/IgG in asymptomatic people, as they will have an immune response even though they don’t display symptoms. The timeline of infection will be the same as someone displaying symptoms.
I didn’t read the results after 10 minutes. What should I do?
For the result, the window of accuracy is 10-15 minutes after you add the sample and buffer solution. If you forget to read the results after this time, the test may not be accurate and you should repeat it.
What is the shelf-life of the test cassette?
The shelf-life is 18 months from the date of manufacture. The product expiry is printed onto the packaging for reference. Do not use after the expiry date.
How should I store the tests?
The recommended storage temperature is 2 – 30°C, however, we do not recommend you store them in the fridge, unless there is a risk of them overheating. Do not freeze the test cassettes or buffer solution. Tests should be performed at room temperature (15 – 30°C), so if you have stored tests in the fridge, you should allow them to reach room temperature before performing a test.
Do any medications, drugs or other proteins in the blood affect the test result?
To date we have tested numerous common pharmaceuticals, none of which have interfered with the test, hence we currently see no cross-reactivity issues. We are looking at more drugs and will update customers accordingly.
How accurate is the test?
We have conducted a number of studies with:
• Kings College London
• Guy’s and St. Thomas’s London
• UZ Leuven Belgium
• The French National Centre for Scientific Research
• Cambridge University
• Imperial College London
• Champalimaud Portugal
and many more.
One such example is the independent evaluation conducted by Guy’s and St. Thomas NHS, London. 503 samples were tested and SureScreen’s test obtained the following results:
Over 98% accurate
Our several clinical studies are evidence of the usability and effectiveness of the test.
Will IgG and IgM remain in the blood after I’ve recovered from COVID-19?
There is some evidence that IgG/IgM remains in the blood after recovery to prevent reinfection. We have tested some patients and noticed that they still test positive for at least 33 days after first displaying symptoms. You won’t be infectious after you recover, even if you test positive, but you should still be cautious as long term immunity has not yet been confirmed and reinfection may still occur.
Can babies and young children be tested?
Yes, there are no issues with testing babies and young children.
Can pregnant or breast feeding women be tested?
Yes, there is no harm to the mother or baby when performing a test.
Is there anyone that shouldn’t be tested?
No, the more people that are tested, the better it will be to understand the spread of the virus, which will result in better measures being taken to prevent its spread. However, as the test requires a blood sample, anyone with a blood-related health condition (such as haemophilia) should discuss this with a healthcare professional before performing a test.
Is the test CE marked? Does it have IVD certification?
Yes, the COVID-19 test is CE marked for professional use and is therefore a registered IVD device.
Has the test been accredited?
The COVID-19 test is CE marked for professional use and is therefore suitable and ready for use by a healthcare professional. In addition to our clinical evaluations already completed on the product, we are currently working with a number of independent laboratories and Departments of Health across Europe to further validate the product and gain best practice approvals.
Do you have a confirmation lab test for Coronavirus to confirm positive samples?
This screening test is designed to be used alongside a robust screening protocol with laboratory confirmations. We would recommend you work within your healthcare institution to ensure the correct protocols are being followed when using this product.