Testing for SARS-CoV-2 Antibodies
2020
Antibody testing can determine previous exposure to SARS-CoV-2 virus. Recently, the UK government has made antibody testing available to anyone wanting it, even if there is no clinical indication. The purpose of this article is to provide guidance for when to consider antibody testing in individuals with and without symptoms suggestive of current or past SARS-CoV-2 infection.
Key points made by the authors include: (1) antibody testing is likely to be most useful 2 weeks after infection, (2) sensitivity and specificity will vary over time and results will need to be contextualized with that in mind, (3) antibody testing could play a role in patients with late presentation, prolonged symptoms, or negative results from reverse transcription polymerase chain reaction (PCR) tests. The authors acknowledge that there is an evidence gap in terms of whether individuals with SARS-CoV-2 antibodies have protective immunity.
The article contains useful graphics and a link to an interactive that allows users to vary prior probability of infection, the sensitivity of SARS-CoV-2 antibody testing, and the specificity of SARS-CoV-2 antibody testing.
Testing for SARS-CoV-2 Antibodies
Source:
Watson J, Richter A, Deeks J. Testing for SARS-CoV-2 Antibodies. BMJ 2020; 370: m3325. http://dx.doi.org/10.1136/bmj.m3325