Objectives: To validate C-reactive protein (CRP), red cell distribution width (RDW), and neutrophil lymphocyte ratio (NLR) for both serious outcomes and length of hospital stay (LOS) among hospitalized coronavirus disease-19 (COVID-19) patients. Methods: Laboratory data of adult COVID-19 patients (n=74) was collected in this retrospective cohort. Logistic regression was employed for risk factor evaluation and receiver operating curve was used for comparison of these risk factors for the prediction of serious outcome. Multiple regression was applied to determine the association between routine analytes and LOS. Results: Higher levels of CRP (3 times), white blood cells (20%), and neutrophil counts (40%) were seen in the serious category. Odds ratio for CRP for the serious outcome was 1.052 ( p =0.007) and RDW for the serious outcome was 1.218 ( p =0.040) in unadjusted model and odds ratio for CRP for the serious outcome was 1.048 ( p =0.024) and for RDW 1.286 ( p =0.023) in adjusted model. In a multivariate regression analysis for the LOS of the unadjusted models consisting of NLR, monocyte lymphocyte ratio (MLR) and platelet lymphocyte ratio (PLR), the beta coefficients (BC) for the CRP were 0.006 (NLR), 0.005 (MLR) and 0.006 (PLR), whereas -0.029 (NLR), -0.034 (MLR) and -0.027 (PLR) were BCs for mean corpuscular hemoglobin concentration (MCHC). Additionally, in adjusted models, the BCs for MCHC were -0.044 (NLR), -0.047 (MLR) and -0.043 (PLR). However, the CRP was consistent with 0.004 (BC) in all models. Conclusion: We observed that CRP is a better predictor than RDW and NLR for serious outcome among COVID-19 patients. Besides, CRP was positively, whereas MCHC was negatively associated with LOS.