The COVID-19 antibody tests have major weaknesses, according to a review of the latest international research published today.
The findings emerged as further evidence emerged of local resurgences of the virus in the UK following the lockdown of the city of Leicester.
A global team of researchers searched medical databases and preprint servers from 1 January to 30 April 2020 for studies that measured sensitivity and/or specificity of a COVID-19 antibody test compared with a control test.
They found eligible studies, 70% of which were from China, with the rest from the UK, USA, Denmark, Spain, Sweden, Japan and Germany.
However, half of the studies were not peer reviewed and most had a high or unclear risk of bias. Four studies included outpatients and two evaluated tests at the point of care.
Writing in The BMJ, the authors say that when they pooled together the sensitivity results for each study, they ranged between 66% and 97.8%, depending on the type of test method used.
They also found that pooled specificities ranged from 96.6% to 99.7%, depending on the test method used, which meant that up to 3.4% of patients were wrongly identified as having COVID-19.
The authors also reveal that pooled sensitivities were consistently lower for the lateral flow immunoassay (LFIA) test – the method that is being considered for “immunity passports” – compared with other test methods.
They warn that based on their results, if an LFIA test is applied to a population with a COVID-19 prevalence of 10%, for every 1000 people tested, 31 who never had the virus will be incorrectly told they are immune, while 34 people who had it will be incorrectly told that they were never infected.
The research also highlighted concerns over commercial test kits, which had 65% sensitivity compared with 88.2% of non-commercial kits.
“These observations indicate important weaknesses in the evidence on COVID-19 serological tests, particularly those being marketed as point-of-care tests,” they write.
“While the scientific community should be lauded for the pace at which novel serological tests have been developed, this review underscores the need for high quality clinical studies to evaluate these tools. With international collaboration, such studies could be rapidly conducted."
* East Kent Hospitals University Foundation Trust accounted for 8% of deaths from the virus in one week last month, it was revealed. The 23 deaths accounted for two-thirds of the fatalities in the south-east of England that week, the Health Service Journal reported.
Leaks from Public Health England, meanwhile, point to rising numbers of cases in Barnsley, Oldham, Rochdale, Bradford and Bedford with potential for local lockdowns in each case.
The UK reported 829 new cases and 176 new deaths from the virus yesterday. The USA reported more than 50,000 new cases and 668 deaths – and Brazil more than 44,000 cases and 1,057 deaths.
Lisboa Bastos M, Tavaziva G. Kunal Abidi S, Campbell JR, Haraoui L-P, Jonston JC, Lan Z, Law S, MacLean E, Trajman A, Menzie D, Benedetti A, Ahmad Khan F. Diagnostic accuracy of serological tests for COVID-19: systematic review and meta-analysis. BMJ 2 July 2020
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