The difference in COVID-19 Fit to Fly Tests
It can be difficult to understand the difference in the array of tests for coronavirus, and what the requirements are for different airlines and countries.
This article is a brief summary of the current state of play. But, one thing to remember is that you should always check with your airline/holiday provider/embassy which tests they will accept and how long before your flight that you will need to have a negative result and a fit to fly certificate. As of yet, there is no international agreement on the type of test nor the timing requirements.
The first thing to understand is the accuracy of the tests. These are measured in:
Specificity tells you the number of people that have tested positive for a test is actually negative called a false-positive. For example, for a sample of 100, a specificity of 90% means that 90 people will show positive and 10 negative whereas in reality all are positive. This is known as a false-positive.
This works in reverse for the Sensitivity accuracy part so using the sample of 100 as an example a sensitivity of 90% means that the tests show 90 people tested are negative and 10 positive whereas all 100 are actually negative. This is called a false-negative.
From the above, you can see that the sensitivity accuracy of a test is really important, as it falsely leads to thinking that more people have a negative result.
Covid tests look for either a current virus infection or previous immune response to an infection (an antibody test). Those that look for current infection are known mainly as diagnostic tests which can be molecular e.g. PCR tests (polymerase chain reaction) which look for the coronaviruses genetic material or antigen tests that can detect specific spike proteins from the virus. Of these tests, the PCR tests (which is the standard NHS test) are more reliable and is most popular with governments.
How are PCR Tests processed?
A swab for the throat or nostrils is taken and this sample is processed by adding a reagent solution to it. This solution is then heated at various temperatures using a thermal cycler to create billions of copies of detectable RNA samples. This genetic material in the RNA sample allows for evidence of Coronavirus and the whole process may take 12 hours as samples are analysed in bulk and results may even take longer due to transport times.
LAMP Tests versus PCR Tests
LAMP (loop-mediated isothermal amplification) is a molecular test and use a similar swabbing method or a saliva sample but don't require the time consuming thermal cycler and can be processed at the venue they are being done. In general LAMP tests have a 79% sensitivity and 100% specificity (good news for uninfected people) when compared to PCR results. Meaning LAMP tests produce a 21% false-negative i.e. 21 out of 100 people think they are negative but are in fact positive. Which is bad news for countries trying to keep out carriers of the virus
TMA Tests versus PCR Tests
TMA ( Transcription- Mediated Amplification Tests ) are also a molecular test similar to LAMP tests but needs heat-treated to produce RNA samples. The process though is quicker and cheaper than the process for PCR testing. At the moment these tests aren't really available in the UK and are accepted in Spain.
Lateral Flow Tests versus PCR Tests
These tests don't need heated ( as are Antigen tests ) and are cheap and quick to carry out and help detect coronavirus immediately. It is due to this that they seem to be the least reliable form of testing achieving on average 58% sensitivity i.e. two out of five people who have the virus are given the all-clear.
Antigen tests often show a positive result a few days after an infected person has a had symptoms for a few days and can be used for university students arriving back to campus with tests being done three days apart to confirm a diagnosis
Timing of tests
Every country is different in terms of how long after the test they expect results either on departure from the airport or arrival into the country. Most require a 72-hour window from when you have had a negative result before arrival at the airport but some require 48 hours while others allow for four, five or even seven days before departure which can add another 12 hours to the time frame depends on where you are travelling to. For example, Portugal requires a PCR test within 72 hours of departure from arrivals from most countries except the UK and EU. This is similar to Spain which requires a test 72 hours before arrival. Spain accepts both PCR and TMA tests but the Canary Islands will only accept an antigen test such as a Lateral Flow. Whilst there is confusion travellers are urged to err on the side of caution and arrive with a PCR test to the Canary Islands and anywhere else in Spain.
Many countries are also asking for tests to be carried out on arrival at the travellers own expense e.g. for Cuba no advance test is required but tickets now attract a Sanitary Fee of £23 which covers a test on arrival and after self-isolating for five days you will have to have a further PCR test. Iceland is similar where you have an option of isolating for 14 days or take a test on arrival and another one five days later
Are tests free?
No Fit to Fly tests is free. The only tests that are free are NHS tests one if you think you have symptoms and must not be used for the purposes of travel.
Where do I get a test?
Many doctors and pharmacies are offering these. Here at Reach Pharmacy, we provide in-store and home tests that you can buy on our website. We only use the highest grade of tests with the best accuracy i.e. PCR tests.
What is "Test and Release"?
This will allow travellers to take a test ( possibly a quick test like Lamp ) on arrival into the UK to half the time in quarantine. Currently, the jury is out but looking like going ahead.