COVID-19 is an infectious disease that can affect your airways and lungs, caused by the most recently discovered coronavirus.
This infectious disease was unknown until the recent outbreak which originated in China in late 2019. At time of writing, cases of COVID-19 continue to rise daily across the globe.
The most common symptoms associated with COVID-19 are fever, tiredness and a dry cough, but symptoms can take up to 14 days to appear so it is difficult to know if someone has been infected ahead of these conditions appearing. In the meantime, infected people can spread the virus unknowingly.
SureScreen's COVID-19 rapid test identifies the body's response to coronavirus after the onset of infection, and gives a qualitative yes/no result within 10 minutes.
Implementing rapid screening for COVID-19 has huge time and cost savings when compared to laboratory screening, and will help to control the spread of the virus by identifying infection rapidly and accurately.
The test cassette is easy to use, needing only a finger-prick sample to function, much like a home blood glucose test.
As well as whole blood, the cassette can also be run with serum or plasma samples.
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.
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 and is a general antibody that can bind to many different types of pathogen. The presence of IgM is an indicator of early infection. IgG is a more specialised antibody that specifically binds to the SARS-CoV-2 virus. The presence of IgG is an indicator of later stage infection (usually 7 days or longer after infection).
The IgG that the test detects is specific to COVID-19, so a positive result would indicate COVID-19 infection. Although the IgM is a more generalised antibody, its presence, combined with IgG and/or the common symptoms of COVID-19, would also indicate infection with the novel SARS-CoV-2 virus. The test can be used for primary and secondary diagnosis of COVID-19.
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.
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.
The test strip has three different lines; one for IgG, one for IgM and one control line. There are four different valid results:
If the control line does not appear, the test is void and should be repeated, irrespective of how many test lines are visible.
If you test positive, you should follow your country’s government’s advice on COVID-19 infection. This usually means self-isolation for 7 days, avoiding contact with others and remaining hydrated. Most cases of COVID-19 are mild and recovery only takes a few days, so there’s no need to panic. Speak to your healthcare practitioner for further advice.
A negative result means the biomarkers are not present in your blood, but you should still exercise caution, as you may still be in the early stages of infection (before IgM levels rise to a detectable level). If symptoms develop, follow the protocols as above and retest as necessary. If symptoms do not develop, it is unlikely you have COVID-19 but should still follow strict hygiene procedures. Ensure you wash your hands regularly, avoid social gatherings and work from home if possible. There’s no need to retest unless you suspect you have contracted the infection and are displaying symptoms.
In this case, there are two options. Either you are infected and may begin to display symptoms in the next few days, or you are infected but are asymptomatic (you won’t display symptoms). In both cases, you should treat it as though you are positive for the virus and should follow the appropriate healthcare guidelines. Speak to your healthcare practitioner for further advice.
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.
If you have the common symptoms of COVID-19 (fever and cough), you likely have contracted the infection and should self-isolate. It is likely your IgG/IgM levels haven’t risen to a detectable level yet. You can be tested again 24 hours later for confirmation id required. Speak to your healthcare practitioner for further advice.
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.
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.
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.
To date we have tested numerous common pharmaceuticals, none of which have interfered with the test. Also, Rheumatoid Factor does not interfere with the test, hence we currently see no cross-reactivity issues. We are looking at more drugs and will update customers accordingly.
We conducted a clinical study in Wuhan, China, where we compared the test cassette to conventional laboratory tests for COVID-19 diagnosis, which also detected the presence of IgG/IgM in 902 blood samples. We obtained the following results:
This clinical study is evidence of the usability and effectiveness of the test.
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.
Yes, there are no issues with testing babies and young children.
Yes, there is no harm to the mother or baby when performing a test.
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.
Yes, the COVID-19 test is CE marked for professional use and is therefore a registered IVD device.
This is a relatively new test but is now being used successfully in many countries around the world.
The COVID-19 test is CE marked for professional use and is therefore suitable for use by a healthcare professional. This test is very new to the market and is an excellent and accurate way to quickly detect COVID-19.
This is something we are looking at, but we would recommend any non-negative results are referred to a medical health practitioner through the NHS who have access to confirmatory testing through a laboratory. Phone 111 from any mobile or landline or visit https://111.nhs.uk/ for further information. Do NOT visit your local surgery to avoid spreading any potential infections.