COVID-19: Are antibody tests reliable? – Naturopathy Naturopathy Specialist Portal
Time of antibody testing determines reliability
Antibody tests play an important role in the diagnosis of COVID-19, as a recent Overview of studies shows. Important is the date on which such Tests are to be carried out is, however. The report summarises to the end of April 2020 globally available research results.
By the independent Cochrane organization performed analysis of various studies, it was found that anti-body test may be useful for the diagnosis of COVID-19, it arrives at the correct time of the execution of the Tests. The results have now been published in the “Cochrane Database of Systematic Reviews”.
How do anti-body tests?
The immune system of COVID-19 diseased people react to the disease with the development of proteins in the blood, called antibodies, which attack the Virus. The detection of antibodies in the blood of people can be an indication of whether you currently have COVID-19 or at COVID-19 were ill.
Why antibody tests are so important
Antibody tests are an important tool of public health to identify at Covid-19 ill persons or people with previous COVID-19-disease. This allows an assessment of the spread of infection and the need for public health interventions.
What was the goal of the analysis?
The researchers took information from many different studies to determine if anti body tests are not accurate enough to diagnose infections with SARS-CoV-2 in people with or without symptoms of COVID-19. In addition, it should be determined whether the Test can be used to find out whether people were already suffering from COVID-19.
Results of 11,000 publications were evaluated
Under the leadership of the University of Birmingham analyzed the Cochrane Researchers from universities around the world, 11,000 of available publications to COVID-19. They tried to find studies that reported the results of antibody tests in groups of people, one of which was known, that you have COVID-19, or had. Investigations were also evaluated for anti-body tests, one of which is known was that they were based on COVID-19.
Results of 54 studies were relevant
The research group found a total of 54 relevant studies, with test results from nearly 16,000 samples. Most of the studies originated from China and were conducted on people who were admitted to hospital.
Three types of antibodies were investigated
These studies examined three types of antibodies, IgA, IgG, and IgM. Most of the Tests measured both IgG and IgM, but some of the dimensions of a single antibody, or combinations of the three antibodies. Data, however, there were only 27 Tests – a small fraction of the over 200 available on the market anti-body Tests. The data were not sufficient to compare the accuracy of the various Tests, report the researchers.
Time of testing is extremely important for reliability
The researchers found that the sensitivity (the proportion of people who had COVID-19, can the of the Test depends on to demonstrate) of an anti-body tests very closely with the time of the execution of the Tests together. Testing of IgG – and IgM-antibodies after 8 to 14 days after the onset of symptoms identified correctly only had 70 percent of the people, the COVID-19. Considered the researchers, however, data derived from Tests that were carried out between 15 and 35 days after the first onset of symptoms, could be 90 percent of the people with COVID-19 correctly identified. There are not enough studies, the sensitivity of antibody tests is about 35 days after the onset of symptoms, in addition to estimate, adds the Team.
How many people fall through the cracks?
With other words: In a sample of 1000 people, 200 people (20 percent) are actually suffering from COVID-19, would receive 193 people with a positive test result, but a 10 (5 percent) of these people have no COVID-19 (false positive result). In addition, 807 persons would receive a negative test result, but 17 (2 percent) of these affected people were in COVID-19 ill (false negative result).
Reliability of the antibody test in the case of mild disease?
The Tests were more reliable in the detection of COVID-19 persons were tested two or more weeks after the onset of symptoms. It is not known how well the Tests work, when they are carried out more than five weeks after the onset of symptoms, report the researchers. It is also not clear whether the observed reliability applies to people with milder disease or without symptoms, because the trials in the Overview were carried out mainly to people who were in the hospital, and thus stronger symptoms.
Important role of anti-body tests
The studies showed that antibody tests could play a role in the diagnosis of COVID-19 people had two or more weeks COVID-19-symptoms, but no PCR Test have made.
Test does not work at the wrong time
Through the evaluation of all available data from around the world, a clear pattern could be discovered, which show that the Timing is in the application of antibody tests is crucial. If one uses such Tests at the wrong time, it won’t work. This first COVID-19-antibody tests show potential, it remains unclear, however, how exactly do you identify COVID-19 in the case of people with mild or no symptoms. It is also uncertain how well they work after more than five weeks after the onset of symptoms, summarises the research group.
Concerns about the quality of the evaluated studies
The researchers also various concerns about the quality of the studies evaluated had. The studies were small and gave their results in full. Many of the Works contain multiple samples from the same patients. More than half of the studies has been provided, before they were reviewed by international experts, reports the researchers.
Additional analyses are already in the planning
The Design, implementation and reporting of studies on the accuracy of COVID-19-Tests need to be significantly improved. The studies must be reported according to the time of occurrence of symptoms of disaggregated data, claim the researchers. Measures are needed to ensure that all the results of the test evaluations are publicly available, thus, selective reporting can be prevented. The research group plans to Check the accuracy of the antibody tests to be updated regularly as more studies are published. (as)