COVID-19 Antibodies: Researchers Warn Of Major Weaknesses And Inaccuracy Of Most COVID-19 Antibody Tests Especially Those From China
: A new research published by the British Medical Journal, (BMJ)
yesterday highlights major weaknesses that exist in the evidence base for COVID-19 antibody tests. https://www.bmj.com/content/370/bmj.m2516
The research found that the evidence is particularly weak for point-of-care tests (performed directly with a patient, outside of a laboratory) and does not support their continued use, say the researchers.
Most of such home use COVID-19 antibody test kits especially those that originated from China should be avoided due to lack of accuracy.
Although serological tests to detect antibodies against COVID-19 could improve diagnosis and be useful tools for monitoring levels of infection in a population, it is critical to use only test kits that are credible.
The British Prime Minister Boris Johnson has described antibody tests as "game-changing" in its response to the pandemic, but it is important to formally evaluate whether there is sufficient evidence that they are accurate.
Hence the international team of researchers set out to determine the diagnostic accuracy of antibody tests for COVID-19.
The researchers searched medical databases and preprint servers from 1 January to 30 April 2020 for studies measuring sensitivity and/or specificity of a COVID-19 antibody test compared with a control test.
The sensitivity evaluation measures the percentage of individuals who are correctly identified as having a disease, while specificity measures the percentage of people who are correctly identified as not having a disease.
Interestingly of 40 eligible studies, most (70%) were from China and the rest were from the UK, US, Denmark, Spain, Sweden, Japan and Germany.
Significantly half of the studies were not peer reviewed and most were found to have a high or unclear risk of bias (problems in study design that can influence results). Only four studies included outpatients and only two evaluated tests at the point of care. (It should be noted that eh China medical studies do not conform to proper international guidelines and in almost 80 % of the time, most of such studies are either faked or inaccurate or manipulated to make their products look good and enhance sales.)
Significantly when sensitivity results for each study were pooled together, they ranged from 66% to 97.8% depending on the type of test method used, meaning that between 2.2% and 34% of patients with COVID-19 would be missed.
Also pooled specificities ranged from 96.6% to 99.7%, depending on the test method used, meaning that between 3.4% and 0.3% of patients would be wrongly identified as having COVID-19.
The pooled sensitivities were consistently lower for the lateral flow immunoassay (LFIA) test compared with other test methods. The LFIA test is the potential point-of-care method that is being considered for 'immunity passports.'
From these results, the authors explain that, 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 COVI
D-19 will be incorrectly told they are immune, and 34 people who had COVID-19 will be incorrectly told that they were never infected.
It should also be noted that pooled sensitivities were also lower with commercial test kits (65%) compared with non-commercial kits (88.2%) and in the first and second week after symptom onset compared with after the second week.
The study team point to some limitations, such as differences in study populations and the potential for missing studies. However, strengths include thorough search strategies and assessment of bias.
Associate Professor Dr Faiz Ahmad Khan, lead researcher from McGill University-Canada told Thailand Medical News, "These observations indicate important weaknesses in the evidence on COVID-19 serological tests, particularly those being marketed as point-of-care tests. 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."
Thailand Medical News advices that when procuring antibody test kits, stay away from those made in China and for individual patients paying for such services at hospitals etc, check where these kits are made from and if they are from China, simply reject it and do not use the clinic or hospital services as inaccurate results could endanger your life and the lives of your loved ones. If public hospitals in your country are using it, check if any corruption issues were involved with the staff procuring such substandard test kits or products from China. Stay away from products sold online and those that do not have your local FDA or regulatory body approval.
For more about COVID-19 antibodies
and test kits, keep on logging to Thailand Medical News.