Abstract:Objective To summarize the clinical characteristics of COVID-19 (Corona virus disease 2019) and bacterial pneumonia, and to explore the clinical value of white blood cell (WBC), C-reactive protein (CRP) and procalcitonin (PCT) combined with detection of T lymphocyte subgroup in the detection of novel COVID-19 and bacterial pneumonia. Methods The clinical data of 35 patients with COVID-19 and 40 patients with bacterial pneumonia were retrospectively analyzing, and all patients were tested for blood routine, CRP and PCT, T-lymphocyte subsets. The clinical data and characteristics of the two groups were analyzed. Results The levels of WBC, absolute value of lymphocytes, CRP and PCT in the COVID-19 group were significantly lower than those in the bacterial pneumonia group, and the difference between the two groups was statistically significant (P?0.05); absolute counts of CD3+, CD4+ and CD8+ in COVID-19 group were significantly lower than those in the bacterial pneumonia group (P?0.05). However, there was no significant difference in CD4+/CD8+ between the two groups (P?>?0.05). Conclusions The combined detection of peripheral blood routine, CRP, PCT and T lymphocyte subsets is helpful for the differentiation of COVID-19 and bacterial pneumonia, especially during the outbreak of novel coronavirus pneumonia, which has important clinical significance for SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection with atypical clinical symptoms and suspected patients.