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COVID-19 TESTS

French experts warn cold temperatures could lead to false Covid test results

French health authorities have warned that cold temperatures can render Covid tests unreliable, as a winter cold snap grips much of France.

A health worker sits in a Covid test tent near the Paris opera.
A health worker sits in a Covid test tent near the Paris opera. French health authorities warn that tests taken in cold conditions may be inaccurate. (Photo by Thomas COEX / AFP)

Hundreds of thousands of Covid tests are conducted in France every single day. 

Many of them are the rapid-result antigen tests conducted in tents set up in the street, often found just outside pharmacies. 

While getting a test is straightforward enough, results obtained via an antigen test in cold conditions should be taken with a pinch of salt, according to health authorities. 

More than a year ago, the French Health Ministry warned of false positives arising from antigen tests taken outside. 

Inaccurate results can occur when temperatures drop below 2C because cold temperatures can influence the chemical reaction that takes place when the solution mixed with your nasal swab sample is entered onto the small plastic test reader. 

Over the winter period, this means that there is a greater risk of inaccurate Covid test results. In the east of France, temperatures reached -3C on Thursday. 

In an interview with Le Parisien on Thursday, the head of a French pharmacists union, Gilles Bonnefond, said there are two ways to avoid false results. 

“The first is to not store the tests in the cold. The advice is to keep the the temperature between 2C and 30C. If the tests are frozen, it completely degrades the silicon mould,” he said. 

Bonnefond said that while the tests can be carried out in tents where the temperature is lower, they should be moved to a space where it is at least 7C-8C while waiting for results. 

He also warned that self-tests should not be stored in cold temperatures prior to use. 

“Users must keep their tests at an ambient temperature. The worst thing is to leave them in the car where it can be very cold,” he said. 

In France, you are encouraged to take a confirmatory antigen or PCR test if you have tested positive for Covid via a self-test. You can more about that HERE

You are also encouraged to get tested if you have come into contact with someone who has Covid and have not been infected within the past two months. 

You can find a full list of testing sites here

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COVID-19 TESTS

Covid home-test kits in France: How to use, where to find and how much?

Home testing kits are increasingly becoming part of the French government's anti-Covid strategy - here's how to find them, how much they cost and what they can be used for.

The French Government is increasingly looking towards self-tests as part of its anti-Covid strategy.
The French Government is increasingly looking towards self-tests as part of its anti-Covid strategy. (Photo by Ben STANSALL / AFP)

The French government sees Covid self-test kits (known as autotests) as a “complement” to its existing infrastructure of more than 12,000 testing sites across the country, offering both PCR and antigen tests.

Over the weekend, the French government spokesperson Gabriel Attal said that pharmacies would receive an extra ten million self-tests this week, as part of the “reinforced testing policy”.

“We will guarantee pharmacies that we will reimburse them for stock that they buy but have not sold, which will incite them to buy more stock,” he told BFMTV.  “We need self-tests to be sold in as many pharmacies as possible” 

Test types 

France offers four types of Covid test;

  • PCR test – a test performed by a medical professional with the sample sent to a laboratory for processing. These are considered the most reliable
  • Antigen test – a test performed by a medical professional (usually in a pharmacy) with results delivered on the spot
  • Self-test – the same as an antigen test, but you do it yourself at home. Self tests and antigen tests are identical, but antigen tests are considered more reliable as they are administered by professionals who are trained in how to collect the sample

All three of the above test types involve nasal swabs.

  • Saliva tests – an antigen test, but instead of a nasal swab, the patient spits into a test tube. Usually used on children or people who, for medical reasons, cannot take a nasal swab test.

Who should take a self test?

School children under the age of 12 are required to take self-tests on Day 2 and Day 4 after coming into contact with someone infected with Covid. Parents are required to sign an attestation sur l’honneur declaring that these tests have been completed. 

Vaccinated children over the age of 12 are required to do the same (unvaccinated children of this age are required to self-isolate for 7 days and then complete a negative PCR or antigen test).

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Among the general population, people who are contact cases are encouraged to take an antigen or PCR test straight away and then carry out self-tests on Day 2 and Day 4 following interaction with the infected person. 

The health ministry has made an instructional video on how to perform self-tests correctly, although each pack should come with written instructions. 

Where can I buy a self-test and how much does it cost? 

Self-tests are available in pharmacies and, up until January 31st, in supermarkets. 

The government has set price limits on self-tests – the maximum price for a single test is limited to €5.20, after being brought down from €6 in May 2021. 

READ MORE Covid self-testing kits to be sold in French supermarkets

Supermarkets generally sell these tests at a lower price than pharmacies – in part because they can buy in bulk. 

Some people also get free tests:

  • Carers who work with old, disabled or immunodeficient people (this covers some 600,000 people in France) can receive ten free tests per month from the pharmacy;
  • Adults and children over the age of 12 who are fully vaccinated can get two free self-tests from the pharmacy if they are a contact case and have just completed a negative antigen or PCR test (which they must present at the counter);
  • Children under the age of 12 who need self-tests to return to school can get them from the pharmacy once proof of a negative antigen or PCR test result is presented at the counter.

How should I interpret my test result? 

If the result of your self-test is positive, you must take either an antigen or PCR test straight away to confirm the result (if you cannot work from home it would be better to take a PCR test, as this is needed to obtain an arrêt de travail). 

Once the result is confirmed, what you do next depends on your age and vaccination status. 

If you are fully vaccinated or if you are under 12 years old, you should isolate for five days following your confirmatory result. After this, you should take another antigen or PCR test. If it is negative and you have no symptoms, you can leave self-isolation. If you test positive or are displaying symptoms, wait two days and then do another antigen or PCR test.

If you are not fully vaccinated, you should self-isolate for a minimum of seven days following your confirmatory result. After this, you should take another antigen or PCR test. If it is negative and you have no symptoms, you can leave self-isolation. If you test positive or are displaying symptoms, wait three days and then do another antigen or PCR test.

Can I use a self-test for travel? 

Self-tests cannot be used for travel to France, and in fact few countries accept the results of home-test kits for travel purposes. 

Whether or not you need a test to visit France depends on where you are coming from. 

Currently, all travellers coming from non-EU/Schengen zone countries must carry out a PCR or antigen test at least 48 hours before departure time. 

Vaccinated travellers coming from a green list country, which includes all EU and Schengen zone nations do not need to take any test at all. Unvaccinated travellers coming from these places must take a negative PCR or antigen test taken within 24 hours of departure time.

All travellers from the UK to France must take a pre-departure test (antigen or PCR) within 24 hours of their departure time. 

Are there any other restrictions on home tests?

Results of a home test kit cannot be uploaded to the Tous Anti Covid contact tracing app.

They also cannot be used to provide proof of recent recovery from Covid – if you need this proof (either for travel or for the domestic if you cannot get a booster due to recently having had Covid) you will need either an antigen or PCR test.

If you test positive for Covid and cannot work from home you will need an arrêt de travail in order to ensure (if you are an employee) that you continue to be paid. This can only be obtained with a PCR test.

Useful test vocab 

Dépistage Covid/Un test Covid – Covid testing/a Covid test 

Un autotest/ test anti-génique/ test PCR – a self-test/antigen test/PCR test

Puis-je utiliser ce test pour voyager? – Can I use this test to travel? 

L’auto-test coute combien? – How much does the self-test cost?

Y-a-t-il un centre de dépistage dans le coin? – Is there a testing centre nearby? 

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