A medical worker wearing full protective gear takes a swab sample from a journalist to be tested for the COVID-19 coronavirus before the second plenary session of the National People�s Congress (NPC) in Beijing on May 25, 2020. (AFP photo)

Doctors� leaders in the UK have demanded an end to the evasion and wall of silence around how many swab tests on NHS staff produce wrong results.

The tests, with samples taken from the nose and throat, are essential in controlling the spread of Covid-19 in hospitals because they are used to check whether NHS personnel and inpatients have the virus and might inadvertently spread it.

Swab tests are notoriously unreliable with as many as 25% of those carried out during the pandemic wrongly saying that a carrier was not infected. Medical research has found that as many as 29% yield a false negative.

The Hospital Consultants and Specialists Association (HCSA) is worried that staff wrongly declared to be virus-free after being tested could lead to patients becoming infected while in hospital.

A study by Public Health England (PHE) last week found that as many as 20% of inpatients and 90% of healthcare workers contracted the virus while in hospital.

In a scathing letter to PHE, the HCSA�s general secretary, Dr. Paul Donaldson, a consultant microbiologist, said, Statements by PHE officials and others place the incidence of false negatives somewhere between 20% and 30%. If confirmed, this is a worryingly high rate which raises the prospect of many infected individuals, possibly without symptoms, being passed fit to return to healthcare settings where they will transmit SARS-CoV-2 to colleagues and patients.

Doctors feel deep concern and frustration at PHE�s systematic lack of information about the different types of coronavirus tests and say a wall of silence seems to have been erected around the issue.

The HCSA is also perturbed that the Department of Health and Social Care (DHSC) has refused to fully answer parliamentary questions which Labour has tabled to find out more about the tests.

Justin Madders, a shadow health minister, requested that the DHSC reveal the rate of false negative tests.

In response, Nadine Dorries, the health minister, said only that viral detection tests have high levels of clinical sensitivity at close to 100%. The staff of NHS laboratories do everything they can to minimize false positives, she said.

Asked by Madders to name all the Covid-19 tests in use, Dorries declined to do so and simply replied, There are eight key testing platforms which deliver the majority of testing. All these tests are clinically validated and have high levels of performance.

Dorries also declined to reveal which tests for Covid-19 the NHS has discontinued using or why but did reiterate that eight clinically validated tests were being used.

Researchers have found that between 2% and 29% of Covid-19 tests produced false negatives. The number of true positive results from nasal swabs was as low as 63% and from throat swabs just 32%, the lead author, Dr. Jessica Watson, reported.

Prof. Andrew Goddard, president of the Royal College of Physicians, said, The main issue from the perspective of physicians has been, until recently, the lack of access to testing as shown by our survey. Even though the test is far from perfect the inability for healthcare and social care workers to access the test for themselves, their patients and their families has hampered our ability to respond to the pandemic and control its spread within hospitals and care homes.

Dr. Nick Phin, PHE�s incident director, declined to respond directly to the HCSA�s concerns. He said, The UK�s national testing system is built on strong foundations using the latest scientific evidence and expert advice. The different tests in use have been assessed as performing to manufacturers� specifications.

SOURCE: PRESS TV