The test is being developed by BioSpeedia, based at the Institut Pasteur in Paris. It is aiming to test whether someone’s blood contains antibodies against Covid-19, which will confirm if they have had the virus or not - even if they had no symptoms.
An early trial on 146 people was deemed conclusive, with a specificity of 98.1 to 100% and a sensitivity of 95.5 to 100%.
Because blood tests look for antibodies to the virus, and not the actual virus itself, they allow testers to check if patients have had the virus even if they have no symptoms, or are now cured. It is estimated that as many as 80% of people with the virus show no symptoms.
This means that the blood tests can not only help to diagnose patients in the later stages of the illness, but also show the extent of the virus’ real spread among the population. It is hoped that this data will help scientists and ministers determine an estimated level of population immunity, and decide when to lift confinement measures.
Read more: France plans more Covid-19 tests as WHO says ‘attack’
Read more: France plans mass Covid-19 blood test post-confinement
In the early stages of the virus infection (5-6 days), the results of the tests come back negative, as the body has not yet created an immune response to the virus. After 7-8 days, the antibodies dubbed “IgM” begin to appear, ahead of further antibodies named “IgG”, which come even later.
This test appears to work close to 100% of the time, said the hospital CHU in Saint-Etienne - where the BioSpeedia test was trialled - which has allowed the hospital to reduce the number of “false negative” tests. These are still possible, however, if the number of antibodies is low.
Yet, Professor Bruno Pozzetto, virologist at the CHU, said: “The results are fairly compelling, and confirm their studies.”
The test is easy to administer, as it works with only a few drops of blood, in the same way as a glucose monitor used by diabetics.
Testers prick their finger with a small medical needle, and drop their blood onto a small plastic tester. After 5-15 minutes, if the test lines go pink, the test is positive for antibodies.
It is expected that the test will first be used by health professionals in hospitals, but may later be rolled out to GPs, and later even self-testing kits for people at home. But more work and “more information” will need to be gathered before this is permitted, said Yves Germani, CEO of BioSpeedia.
The successful tests at the CHU in Saint-Etienne are expected to help push the studies forward even more quickly.
Mr Germani said: “We were practically on cloud nine when Professor Bruno Pozzetto confirmed the results in his service. We immediately came to the area from Paris.”
He explained that while clinical trials are continuing, work has now finished on the test prototype. He said: “We are in the process of setting up the production line, but we [will] have capacity to produce a thousand tests within about three or four days.”
The next step will be to obtain approval from medical safety agency l’Agence Nationale de Sécurité du Médicament (ANSM), and to get the European Union CE safety certification.
Mr Germani said: “Once this test is certified, we could move to 40,000 tests per week, and then even increase it further.”
Wider population testing
The news comes after health minister Olivier Véran announced that many local scientific laboratories - such as those in town centres - are to be given authorisation to test for Covid-19.
He said: “Labs in hospitals, in town, in departments, at vets; research labs, gendarmerie and police” will all be mobilised into the testing effort.
“I hear and salute all those who have volunteered to take part in the national testing effort,” he said, explaining that authorisations will be given to labs over the weekend, with tests beginning on Monday April 6.
The news comes after president of the national union of biologists, François Blanchecotte, said that widespread testing of the population was “almost the only” method that would allow France to come out of confinement.
He said: “We must prepare the French, so that they know if they have contracted the virus or not, whether or not they had symptoms.”
Authorising tests at the 4,000 national labs in France “will allow us to test the French public on a wide scale”, he said.
Even veterinary labs will be mobilised, as veterinary medicines are being used to help cure humans currently. Two medicines, based on the drug propofol, have been authorised for use against Covid-19 in intensive care units in France, to deeply sedate intubated patients to help with artificial breathing.
Jacques Guérin, president of vet council Le Conseil National de l’Ordre des Vétérinaires, explained why vets had requested to take part in the testing effort. He said: “The veterinary sector is used to dealing with epidemic illnesses, after all.”
However, local testing is not currently being rolled out to the general population.
Tests will only be administered for at-risk people with symptoms, for hospitalised patients, or for carers and healthcare workers.
If you have not been prescribed a test by a healthcare worker or doctor, you are still not entitled to one.
