Antigen test accuracy rate ‘does not sound right’, says HSE clinical lead

Colm Henry questions accuracy, as antigen tests to be sold at Circle K petrol stations

A Covid-19 antigen test. File photograph : Laura Hutton/The Irish Times

A Covid-19 antigen test. File photograph : Laura Hutton/The Irish Times

 

The HSE’s chief clinical officer, Dr Colm Henry has expressed concern about the accuracy of antigen tests due to be sold at petrol stations.

The Circle K chain of filling stations is due to start selling the 15-minute antigen tests, which it says are European Union-certified and have a 97.83 per cent accuracy rate.

Dr Henry told Newstalk Breakfast that while he did not know the details and had not been to a Circle K filling station or seen the test, the accuracy figures did not “sound right” to him.

“We look at the sensitivity of the test based on how readily it picks up a test on self-testing compared to our gold-standard PCR test. Let’s not forget the purpose of the tests we have – it’s a public health test.

“It’s in the best interests that we pick up truly infectious cases – not just people who are symptomatic, people who are pre-symptomatic or people who are asymptomatic carrying the virus. And the PCR test is by far the most effective test for that purpose.”

Dr Henry said he would be concerned that somebody who should get a PCR test if they’re symptomatic, or think they may have Covid, would rely on the antigen test and behave accordingly. They should “do the right thing” and get a more sensitive PCR test, he said.

Antigen testing had a role as part of the overall Covid response, he said, “but like anything else, you don’t pick it out and displace everything else and say ‘just because I’ve an antigen test everything else is fine, and it absolves me from anything else I have to do in relation to Covid-19’.”

When asked about the mixing of vaccines or the length of time between first and second doses of AstraZeneca, Dr Henry said there was a case for the mixing of vaccines, but essentially the National Immunisation Advisory Committee had to condense all the different opinion and evidence and “out of that, manufacture a simple, single advice for the vaccination programme for people as things stand based on what we know today”.

In a statement, Dr Linda Nolan, managing director of MyBio, the company which manufactures the antigen tests, defended their accuracy.

“Dr Colm Henry is not in a position to challenge the accuracy of the test because these tests have been validated independently and certified in Europe,” she said.

The tests had been verified by a certified body in Germany, Dr Nolan said.

“These tests have been compared with the gold standard PCR tests and the calculation of sensitivity, specificity and accuracy have been made on that basis,” she said.

“It is really surprising and disappointing that the HSE’s chief clinical officer Dr Henry has assumed that this is not the case. MyBio is happy to explain to Colm how to calculate the accuracy of the test,” she said.