Assessing the Severity of COVID-19 Disease Using C-Reactive Protein as a Prognostic Indicator

C-reactive protein (CRP) is a non-specific homopentameric acute phase protein that is produced by hepatocytes and elevated in acute infection or inflammation.The use of CRP as a biomarker in COVID-19 may present a quick and accessible tool in clinical management, trigger longer periods of enhanced observation, provide information around likely disease progression and assist with early therapeutic, ventilation and palliative care discussions.The study was a hospital -based retrospective analytical study.The study was done in PIMS, a tertiary care centre, situated in Puducherry, Tamil Nadu, South India and it is a designated covid hospital (by Government of Puducherry).The C-reactive protein (CRP) values were collected from the section registers for the period of one and a half years (May 2020 to December 2021, which includes all the three waves of covid 19 infection).Highest CRP value recorded in this study was 305 mg/L.Optimal cut-off threshold (Youden index) for CRP was 38.6 mg/L (For severe covid 19 disease).ROC curve and its co-ordinates corresponded to a CRP value of 38.6 as the best cut-off threshold for severe covid 19 disease.With this cutoff threshold, it gave maximum sensitivity of 76.5% and specificity of 74.8%, positive predictive value (PPV) of 67.48%, and negative predictive value (NPV) of 98.62%.A threshold cut-off of CRP 36.8 mg/L proved to be a good predictor of severity of covid 19 disease.