Role of some serological markers in evaluation COVID-19 infection severity

Received: June 7, 2023; accepted: July 13, 2023. Covid-19 is considered an epidemic disease that causes increasing the levels of some inflammatory proteins and biomarkers such as interleukins and acute phase proteins. Therefore, these biomarkers could be useful in knowing and monitoring the severity of disease. This study investigated some biomarkers that related to the immunological response including D-dimer, C-reactive protein (CRP), and interleukin-6 (IL-6), and their effects on the severity of infection and early diagnosis of Covid-19 patients. This retrospective study employed two groups of patients' information to investigate the effects of some immune factors associated to Covid -19 with the first group of 30 confirmed COVID-19 patients aged from 15 to 92 years old and the second control group of 30 patients aged from 18 to 73 years old. All patients' blood serum levels of CRP, IL-6, and D-dimer were measured by using Afias-6 luminescence immunoassay and compared between the two groups. The results showed that the highest level of the biomarker was D-dimer at a mean 2,029.65 ± 143.31 ng/mL, followed by CRP at 88.46 ± 10.41 ng/mL, and then, IL-6 at 26.03 ± 4.61 ng/mL. The highest percentages of these biomarkers were detected at the ages between 15 and 30 years old for D-dimer at 3,642.73 ± 126.44 ng/mL, 47 to 62 years old for CRP at 116.89 ± 16.61 ng/mL, and 79 to 94 years old for IL-6 at 60.57 ± 10.23 ng/mL. In addition, the rates of CRP, D-dimer, and IL-6 were the highest in females compared to males with CRP of 92.42 ± 10.44 ng/mL and 83.71 ± 7.84 ng/mL, D-dimer of 2,200.34 ± 158.77 ng/mL and 1,834.55 ± 251.27 ng/mL, IL-6 of 29.51 ± 6.27 ng/mL and 22.06 ± 6.88 ng/mL for females and males, respectively. Moreover, the results of the correlation coefficient (R) showed high correlation between those biomarkers. The R values of CRP/D-dimer, CRP/IL-6, and D-dimer/IL-6 were 0.343, 0.151, and 0.121, respectively. The results of this retrospective study concluded that COVID-19 infection significantly affected D-dimer, CRP, and IL-6 percentage in the patients, and those biomarkers could be used to monitor the severity of disease progression.