Background In symptomatic patients, the diagnostic approach of COVID-19 should be holistic. We aimed to evaluate the concordance between RT-PCR and serological tests (IgM/IgG), and identify the factors that best predict mortality (clinical stages or viral load). Methods The study included 242 patients referred to the University hospital of Kinshasa for suspected COVID-19, dyspnea or ARDS between June 1st, 2020 and August 02, 2020. Both antibody-SARS-CoV2 IgM/IgG and RT-PCR method were performed on the day of admission to hospital. The clinical stages were established according to the COVID-19 WHO classification. The viral load was expressed by the CtN2 (cycle threshold value of the nucleoproteins) and the CtE (envelope) genes of SARS- CoV-2 detected using GeneXpert. Kappa test and Cox regression were used as appropriate. Results The GeneXpert was positive in 74 patients (30.6%). Seventy two patients (29.8%) had positive IgM and 34 patients (14.0%) had positive IgG. The combination of RT-PCR and serological tests made it possible to treat 104 patients as having COVID-19, which represented an increase in cases of around 41% compared to the result based on GeneXpert alone. The comparison between the two tests has shown that 57 patients (23.5%) had discordant results. The Kappa coefficient was 0.451 (p < 0.001). We recorded 23 deaths (22.1%) among the COVID-19 patients vs 8 deaths (5.8%) among other patients. The severe-critical clinical stage increased the risk of mortality vs. mild-moderate stage (aHR: 26.8, p < 0.001). The values of CtE and CtN2 did not influence mortality significantly. Conclusion In symptomatic patients, serological tests are a support which makes it possible to refer patients to the dedicated COVID-19 units and treat a greater number of COVID-19 patients. WHO Clinical classification seems to predict mortality better than SARS-Cov2 viral load.
【저자키워드】 COVID-19, Mortality, RT-PCR, Symptomatic patients, Serological tests, Concordance, 【초록키워드】 serological test, IgG, IgM, ARDS, hospital, diagnostic, Clinical stages, RT-PCR, Viral, Symptomatic patients, Serological tests, Concordance, Viral load, IgM/IgG, clinical, Dyspnea, SARS- CoV-2, Patient, death, WHO, university, Admission, patients, predict, COVID-19 patients, Combination, Cox regression, Cycle threshold value, COVID-19 patient, referred to, best, Support, Factor, university hospital, Stage, treat, positive, Kappa coefficient, approach, Clinical stage, Result, greater, shown, identify, performed, evaluate, significantly, were used, expressed, increase in, recorded, increased the risk, WHO classification, 【제목키워드】 serological test, SARS-CoV2 infection, Serological tests, symptomatic, predictor,