The following is from Concierge Medical.

This update has a slightly different slant based on the number of enquiries we have received over the past week regarding Covid-19 home testing.

COVID-19 Testing

 This is a constantly evolving picture, and continues to raise many questions for our clients. We will continue to monitor the current advice and evidence, and give our opinion as to what we feel is the best approach to testing generally, whilst highlighting some of the pitfalls in this rather complex subject.

We explored in our last bulletin the different types of testing for Covid-19 currently available, ‘antigen v antibody’ and the reliability of these tests generally. We have had many questions specifically around antibody testing.

 ANTIBODY testing

Antibody testing tests for the body’s immune response to Covid-19 by measuring one or two different antibodies (immunoglobulins) that the immune system generates in response to any infection. This can take from a few days, but more usually a few weeks after infection, to develop. It does not test for the disease itself.

The real value of antibody tests are from a public health perspective, allowing detailed analysis of the spread of disease in the greater population, which will be critical for leaving the ‘lockdown’ situation we are currently in. For this to happen, the tests obviously need to be reliable and accurate, but also organised and conducted on a large scale in a controlled way. There are further uncertainties however, as Covid-19 is a new disease:

• It is unclear as to the best time to test for antibodies. It is believed to be a minimum of 21 days post the start of any symptoms, but maybe longer. Testing before this time increases the risk of under-detection.

• It is unclear how long the Covid-19 antibodies remain in the system. They may well disappear completely after time.

• We simply do not yet know whether possessing antibodies to Covid-19 does actually afford protection to further exposure to the virus, in the medium or longer term.

• Nor do we know whether any immunity will be present against newer variants or ‘mutations’ of Covid-19.

• Also it is very likely that people who suffer a mild or asymptomatic disease may generate a much smaller antibody response, again resulting in under-detection.

Currently, there are two ways of conducting these tests, both involving giving a sample of blood. Firstly, by having blood taken from the arm, and having the sample sent to a laboratory, as you would for any other blood test. Very few laboratories are currently undertaking these tests in the private sector as they have offered their equipment for NHS usage. We have yet to hear any details on what this NHS testing might look like. We are in regular communications with the laboratories, so will keep you informed if this changes. The second option is the ‘pin prick’ test:-

Home and ‘finger prick’ tests

 These are new tests produced by an ever increasing number of manufacturers globally. The ‘rush’ to get these to market has meant that the usual stringent validation and approval that would normally apply to any medical device, simply has not occured. The ‘test of the test’ has not happened, which has led to growing uncertainty on their validity.

We heard from Mr Hancock that the government had ordered around 18 million such tests from a Chinese manufacturer. On further analysis of these tests by Oxford University, they were found to be inaccurate. That is, there was a very real risk of testing negative when you were in fact positive. This has huge ramifications in safety terms, particularly for those wanting to know Covid-19 status prior to caring for an elderly or vulnerable relative or friend.

So we start to see some of the difficulties with a test that is inherently unreliable. No test is ever 100% accurate, but there are certain scientific thresholds that need to be achieved to make it at all useful. These tests have been developed at time of crisis, and validated with very small samples, sometimes as low at 60 individuals. 

Only yesterday, the body that regulates medical devices in the UK (Medical and Healthcare Products Regulatory Agency - the MHRA) published its first guidance on the ‘acceptable’ and ‘desirable’ standards that any approved finger-prick test should meet. Unsurprisingly, these are very rigid and set the bar rather high. This will result in further tests being rejected for falling well below these standards. At least there is now clarity on what a ‘good test’ might be, but as yet, as highlighted above, we are still no further in knowing how and when any test should be conducted, nor understanding the limitations and how best to implement a testing strategy.

 It is also worth noting that in the UK it is currently illegal for any manufacturer to market these tests as ‘home test kits’. Please do not be tempted to source these from any on-line or less than reputable supplier. Currently the advice from Public Health England and the MHRA is that there are no CE-marked approved tests, and that the use of home testing kits is not advised. The links are here for those interested.

https://www.gov.uk/guidance/guidance-on-coronavirus-covid-19-tests-and-testing-kits

https://www.gov.uk/government/publications/covid-19-rapid-tests-for-use-in-community-pharmacies-or-at-home

Some recent observations

 In recent days we have been made aware of private doctors offering to travel from outside our region to undertake Covid-19 tests on anyone requesting them (often at greatly inflated cost). Others have encouraged patients to attend clinics in London and The Midlands to be tested.  

In practical terms, neither scenario would count as an exemption from the current lockdown travel guidelines. To be absolutely clear, unnecessary travel to a clinic for testing, especially in London or any other city, is putting yourself at heightened risk of infection. Inviting a ‘health professional’ (who may have themselves visited dozens of positive cases) to your home, to conduct a test would be equally concerning. 

Whilst we completely understand that many of you will ‘want to know’, maybe having suffered symptoms over the preceding weeks, or desperately needing to return to work, we would ask you to consider the current national guidance on travel and, equally, if not more importantly, that the test being offered is likely to be wholly unreliable at present.

• “Will this test actually change my behaviour at the moment?”

• “Am I exposing myself (and my family) to a heightened risk of infection?”

•   “Can I believe the result anyway?”

  In summary

• Even though we completely understand the uncertainty some of our clients are facing at present, we continue to find it difficult to recommend any form of testing for Covid-19 outside the hospital setting. Accordingly, we have returned the test kits we have purchased due to their inherent inaccuracy

• In particular, the current ‘finger prick test’ seems extremely inaccurate. We will continue to monitor this situation and let you know as soon as a reliable testing process exists

• No ‘home testing’ kit is approved from UK usage. Anyone marketing such kits is acting illegally. 

• Be wary of private clinics and doctors offering any of these tests. If you would like to forward us any data and evidence on their accuracy, we will happily comment and feedback to those concerned, or any appropriate regulatory bodies.

Please contact your doctor if there are any points you would like to discuss in more detail.