Optimize Clinical Laboratory Diagnosis of COVID-19 from Suspect Cases by Likelihood Ratio of SARS-CoV-2 IgM and IgG antibody

Feng Yangchun

The copyright holder for this preprint (which was not peer-reviewed) is . https://doi.org/10.1101/2020.04.07.20053660 doi: medRxiv preprint obtained from "Diagnostic Value of Combined Detection of Serum 2019 novel coronavirus IgM and IgG Antibodies in novel coronavirus Infection", the diagnostic performance index of tandem test cannot be analyzed in this paper. However, this study solves the problem by calculating the posterior probability through the LR+, and proves that the posterior probability of the two antibodies tandem test is much higher than each single antibody detection, while the posterior probability of single antibody detection is not much different. This shows that the single antibody test does not significantly increase the confidence of clinicians in the clear diagnosis of confirmed cases from suspected cases. However, the two antibodies tandem test obviously improved this confidence, making the clinician's confidence in diagnosis increased to 99.15%,which is helpful for clinicians to optimize the diagnosis process by quantification method. By the study, the clinical pathway for clinicians to diagnose COVID-19 was that, for suspected cases, IgM and IgG antibody tests should be firstly done at the same time. If the antibody tests are all positive, COVID-19 can be confirmed. If not, nucleic acid detection (one or more times) is performed, and in extreme cases, high-throughput viral genome sequencing is performed [11] .