Clinical and diagnostic value of the combination of lymphocyte count and creatine kinase in the detection of coronavirus 2019.

The present study aimed to investigate the diagnostic efficiency of the absolute number of lymphocytes (LYM) and creatine kinase (CK) levels in the diagnosis of coronavirus disease 2019 (COVID-19). For this, the clinical data from 84 patients with COVID-19 admitted to Tianjin Haihe Hospital (Tianjin, China) between January and February 2020 were collected. The patients were divided into the following groups: The common COVID-19 group (n=61) and severe COVID-19 group (n=23). In addition, 30 healthy subjects were included as a control group. The results demonstrated that the percentage of neutrophils (NEU%) was significantly increased, while the absolute number of white blood cells, LYM and the percentage of lymphocytes (LYM%) were significantly decreased in patients with COVID-19. Furthermore, in the severe group, the absolute number of red blood cells in female patients, the NEU%, the neutrophil-to-lymphocyte ratio (NLR) and the serum levels of interleukin-6 and C-reactive protein (CRP) were markedly elevated, while those of LYM and LYM% were significantly decreased (all P<0.05). In addition, in the receiver operating characteristics curve analysis for the combination of LYM + CK, the area under the curve values were 0.96 and 1.00, with a sensitivity of 95.08 and 100%, specificity of 86.67 and 100% and cut-off values of 0.42 and 0.50 for the common and severe COVID-19 group, respectively. The results indicated that the diagnostic efficiency of LYM + CK was higher than that of each single factor. Finally, a moderate correlation of lactate dehydrogenase with CRP and NLR (r=0.492 and 0.433, respectively; both P<0.05) was obtained. Overall, the results of the present study indicated that the values of LYM and CK were associated with the progression of COVID-19, suggesting that the combination of both factors may be of clinical diagnostic value for COVID-19.