Our Methods

Understanding our testing

PCR Swab Test

Available as a home-kit or in-clinic test.

This test is a swab of the back of the mouth (tonsils and pharynx) and the nose. Your sample is analysed using the latest PCR technology in conjunction with our partner laboratories. It is a molecular assay based on the detection of the viral nucleic material (RNA) within the covid-19 coronavirus. For quickest turn-around times, we recommend visiting our North West London clinic where clients can self-swab themselves in a private booth or book a slot with one of our trained swabbers. The test can also be done at home in the comfort of your own home, following a set of simple instructions with proper care and attention.


To ensure the quickest turn-around of our home-kits, your package comes with equipped with a postage stamp which sends your sample directly to our testing partner London Medical Laboratory. There it is analysed using the latest PCR technology. 

PCR Results

You will usually get your results, which will confirm whether or not there has been any virus found on your swab, within 24-48 hours of our laboratory receiving your sample. This time table can not be guaranteed in these uncertain times but so far it has been achieved by far the majority of the time. Testing at our clinic ensures quicker results as we aim to send your sample to the laboratory that day.


If your result comes back positive (ie confirming that there is covid-19 DNA/RNA on your swab) then you can be very sure that you have coronavirus in your nose or throat. The implications of this, whether you feel ill or not, is that you can spread the virus and you should check the latest NHS advice here: https://www.nhs.uk/conditions/coronavirus-covid-19/. This is particularly the case if you feel unwell or short of breath at all in which case you should go straight to https://111.nhs.uk/service/COVID-19/ where you will find what to do next.


If you get a negative result (ie confirming that no covid-19 DNA/RNA was found on your swab) then it is cautiously good news but does not completely guarantee that you have not been exposed to covid-19. All it definitively confirms is that there was no covid-19 on the swab. This means that there is a chance that you have swabbed yourself in a window when there were no viruses there or you did not swab effectively enough – so if you do begin to feel any of the symptoms of covid-19 coronavirus please seek help. The guidance on what to do is changing fast as more is being learnt about the virus all the time so please always refer to the latest NHS advice.

IgG Antibody Test

Testing carried out at our Private London Clinic.

This tests your blood for the presence of antibodies that your body has produced in response to being exposed to the virus. It is only very recently - in April, that reliable tests for the presence of antibodies have been made available here. Our IgG test is Public Health England approved and produced by one of the world's foremost diagnostic providers, millions of which are being shipped to the NHS here, to Europe and the world to be used in the frontline of detecting the spread of SARS-Cov-2 coronavirus through our communities. It is PHE approved, FDA EUA approved and CE marked. 

IgG Results

You will get your results within a day of your blood sample being received by our laboratory partner. If you are tested before 2pm at our clinic, we will aim to have your sample sent to our laboratory partner that day. Your result will let you know whether IgG antibodies have been detected or not. 



This test has proven to be 100% accurate in identifying antibodies to SARS-CoV-2 coronavirus at 14 days after onset of Covid-19 symptoms*. Or put another way, everyone who had an illness that was confirmed to be caused by covid-19 developed IgG antibodies 14 days later so there were no false negatives.



It is 99.63% specific. Or put another way, Only 0.37% of over 1000 people tested who could not have been exposed to SARS-CoV-2 showed a false positive result. Interestingly there were over 70 people who had other similar respiratory illnesses tested in this group and none of them showed any false positives so it seems very unlikely that this test picks up antibodies to any of the other viruses that cause symptoms like covid-19. This problem with cross-reactivity was a very major concern about many of the cassette tests that were rushed to market.



Please note that there is still a lot to learn about this virus and having antibodies does not mean you definitely have immunity. Also, it is not yet clear how long immunity lasts, even if there is any. So please do not stop adhering to social distancing, government advice and protective measures just because you have received a positive result. While there is still a lot of uncertainty, it is likely and that you may have at least some temporary immunity when antibodies are detected. 

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0333 577 0939

Unit 6 Minerva Bus Centre, 58-60 Minerva Road, Park Royal, London, NW10 6HJ

Claret Diagnostics is a branch of London Medical Laboratory. London Medical Laboratory are regulated by the Care Quality Commission. Certificate number: CRT1-4708702735