Why Do People Get False Negative PCR Results in Covid Tests? – .

Why Do People Get False Negative PCR Results in Covid Tests? – .

People are urged to self-isolate if they show symptoms of Covid-19 even if they have a negative PCR test result amid issues with false negatives.

There have been a number of cases where people have tested positive using lateral flow testing – but then received a negative PCR result.

Trish Caller tested negative for Covid-19 after using a PCR test – but ended up being admitted to Musgrove Park hospital with both Covid and pneumonia after her symptoms worsened.

Trish returned a negative PCR test result but ended up having covid. She had to be hospitalized for the virus and pneumonia Credit: ITV Western Countries

I lost all confidence in the tests’

She is now recovering at her home in Taunton – but says she has lost faith in the testing system.

Trish told ITV News West Country: “I have lost all confidence in the tests. Why do these tests not resume [Covid]?

“It’s Covid, that’s what it was developed for. I had Covid, 100%. “

Pamela Constable, from Shipham in Somerset, says she has also suffered from the testing system.

Pamela felt that the negative result of her PCR test was incorrect. She booked a second PCR test which confirmed she had the virus Credit: ITV Western Countries

She recently tested positive via several home lateral flow tests, but subsequently received a negative PCR result.

The nursery nurse was surprised by the gap and reserved a second PCR test before returning to work as a precaution.

She said, “By Monday morning my symptoms got worse. I don’t normally work on Mondays, so I didn’t go to nursery that day. I did another PCR test and it was then positive. “

She said she could have passed the virus to other people if she had accepted that first negative PCR result: “The normal protocol is if you have positive lateral flow and you get negative PCR you continue. as usual.

Discrepancies in the results of lateral flow and PCR tests have meant people are urged to self-isolate if they are symptomatic Credit: ITV Western Countries

“If I had to do this, I would have taken this to a nursery with a lot of kids, staff and a lot of parents.

“It’s quite worrying, that you can easily pass this on to someone else without realizing it and that you trust these tests.

“I am also at high risk. You could potentially give this to someone else who is considered high risk. “

Impacts on education

The problem has severely affected schools and education, including the Katherine Lady Berkeley School in Gloucestershire, where more than 40 students and six staff have been forced into self-isolation due to the coronavirus.

Just under 3% of the school’s population is absent due to the virus – which is lower than the national average – but precautions are in place as staff and students have had positive lateral flows followed by results PCR negative.

Elsewhere, Matthew Evans, the principal of Farmor’s School in Fairford, asked for clearer advice on self-isolation rules after suffering a major disruption in the school schedule.

He said: “In the past two weeks we think we lost about 60 days of school due to positive lateral flow tests which then came back with negative PCR.

“And that’s about the same as the number of days we lost for the true positive cases who had to self-isolate for 10 days each.

“I’m really interested to know why this is happening. In the meantime, it will be helpful to have more advice on how schools should react and what we should say to students and parents. “

Why do people get false negatives?

Some academics say the tests aren’t the problem and one explanation is that people don’t do them correctly.

Dr Bharat Pankhania, an infectious disease expert at the University of Exeter, believes people need to be more careful when dabbing their nose and throat during testing.

He said, “For us, getting a really good sample is like scratching.

Infectious disease expert Dr Bharat Pankhania says PCR tests come back negative because people don’t take them correctly Credit: ITV Western Countries

“You really have to put that PCR swab deep in there, scrape and scoop up the cellular material, which is then placed in the PCR tube and analyzed.

“And unless you do a good scratch, a good sample, you might not pick up much and therefore you get a false negative.” “

What are the rules for testing and self-isolation?

Susan Hopkins, Chief Medical Advisor at the UK Health Security Agency, said: “We have been made aware of some areas reporting positive LFD test results with subsequent negative PCR tests and are investigating the cause.

“If you do get a positive LFD test, it’s important to make sure that you then get a follow-up PCR test to confirm that you have Covid-19.

“If you have symptoms of Covid-19, isolate yourself and take a PCR test. With any testing, it is important to carefully read and follow the instructions for use on the test kit to avoid incorrect readings. “

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