Are coronavirus tests and case numbers accurate? - Worldwide question | QHA media

Are coronavirus tests and case numbers accurate? - Worldwide question

25 March 2020, 16:34
Canan Kevser

New cases of the novel coronavirus continue to increase worldwide, with 438,372 confirmed global cases of COVID-19 and total of 19,650 as of today, according to the World Health Organization (WHO). That includes 81,218 cases and a total of 3,281 deaths in China. 

Some have questioned the accuracy of the statistics released by the Chinese government regarding the reported number of cases and deaths due to the outbreak. Also, as QHA reports, over 14 million mobile phone line contracts were cancelled within 2 months of the outbreak of the coronavirus pandemic in China. Now there are concerns about the accuracy of the laboratory tests used to confirm diagnoses.

Reports suggest some people test negative up to six times even though they are infected with the virus. Such was the case with Aytaç Yalman, Former Land Forces Commander of Turkey, who tested negative at first but died shortly after and his wife also tested positive for coronavirus. Mr Aytaç Yalman was the third person who has died from coronavirus in Turkey.

False-negative test results, where patients are told they do not have a condition when they actually do, cause several problems. Patients may be turned away from hospitals and medical facilities when they require care. They may infect others at the outside. Patients’ conditions may also worsen without treatment.

When faced with a highly infectious, potentially deadly pathogen, even a small number of false negatives can have a potentially serious and widespread impact on the larger population.

Accuracy of the coronavirus test results are questioning worldwide

According to research published on the US National Institutes of Health, National Library of Medicine, in a specific subset of those tested in China — asymptomatic contacts of known cases — the tests wrongly found them to be positive 47% of the time.

Dr Li Wenliang, the ophthalmologist who first identified the outbreak and was reprimanded by Chinese authorities when he tried to warn others, developed a cough and fever after unknowingly treating an infected patient. He was hospitalized, testing negative for coronavirus several times before eventually receiving a positive result. He died on February 7 in Wuhan, the epicentre of the outbreak.

The CDC previously admitted test kits they distributed resulted in inconsistent results due to a problematic reagent required for the test. They are now manufacturing the reagents using stricter quality control measures. 

Also, according to recent news published on Czech media, Coronavirus rapid tests from China have an error rate of up to 80%. According to the regional hygienist Pavla Svrčinová, who talked after the Regional Crisis Staff meeting on Monday, error rate of the rapid tests for coronavirus detection is about 80 per cent. It has reported that the Moravian-Silesian Region in the Czech Republic will continue to rely on laboratory testing which allows them to handle only about 900 samples a day.

On the other hand, according to the Deputy Ministry of Health Roman Prymula, the error rate of quick tests from China was known and openly admits that the test is not conclusive but only indicative. According to him, the error rate is not up to 80%, as hygienists say, but only 20% to 30%.

The U.S. also questioned if the tests are reliable. “At a time when the Trump administration is facing intense criticism for its failure to make coronavirus tests available to millions of nervous Americans, remarks by a federal health official on Tuesday appeared to suggest that the World Health Organization’s diagnostic tests were wildly inaccurate.” The New York Times reported. It has claimed that W.H.O. had offered tests to the United States but the U.S. didn’t buy them. The claim objected with a fact that the W.H.O. does not sell tests to wealthy countries, which usually prefer to make their own. According to the W.H.O. website, China, Hong Kong, France, Germany, Thailand and the United States have all designed their own tests. Dr Anne Schuchat, deputy principal director of the Centers for Disease Control and Prevention, confirmed that the W.H.O. gave test kits “primarily to under-resourced countries.”

Why Are Coronavirus Tests Inaccurate?

Studies show that tests may produce false negatives due to laboratory error or insufficient amount of viral material collected from the patient. Samples that are stored or handled improperly also result in false negatives.

Tests may result in false negatives if the patient is tested too early in the course of infection and there is an insufficient amount of virus to be detected. Improper sampling may result in a false negative.

Professor Paul Hunter of the University of East Anglia told Science Media Centre that previously suspected cases of the illness are now considered confirmed cases even though some may be caused by illnesses other than COVID-19. In short, Clinical diagnosis may lead to overdiagnosis and misdiagnosis in some cases.

“People may prevent or lower the risk of this viral infection by good hygiene, avoiding contact with infected people, not going into an outbreak area, and by leaving an outbreak zone.” doctors say.