Possibility of blood test parameters usage in the evaluation of COVID-19 patients’ inflammatory status

Background: C-reactive protein (CRP) is a key laboratory biomarker for anti-inflammatory treatment initiation. Unfortunately, biochemical blood analyzers are not always easily accessible in medical institutions located far from major regional health facilities.

Aim: To develop an approach for inflammatory status estimation based on blood test results in patients with COVID-19 in cases with limited laboratory equipment availability.

Methods: The present retrospective study included 423 patients (male 54.6%; female 45.4%; mean age 59.1 years) receiving hospital treatment due to COVID-19 in Medical Research and Educational Center of Lomonosov Moscow State University from April 21st to June 13th 2020. All patients donated blood for full biochemistry and hematology testing and underwent chest computer tomography (CT).

Results: CRP levels (>60 mg/L) qualitative estimation model was developed based on hematologic test results. It included erythrocyte sedimentation rate and neutrophils to lymphocytes ratio. According to the results of Receiver Operating Characteristic (ROC) analysis present model was characterized by sensitivity of 70.2%, specificity of 74.6%, and area under the ROC-curve of 0.781. Comparison of key clinical parameters reflecting COVID-19 severity, such as length of hospitalization, lung damage at CT (hospital admission and discharge), revealed statistically significant difference between groups with routinely measured CRP levels ≤60 mg/L and >60 mg/L for all the above-mentioned parameters (p <0.05). These differences remained significant when measured CRP levels were substituted with estimated CRP values, indicating interchangeability of these approaches to CRP levels determination, regarding clinically important parameters.

Conclusions: Presented model for inflammatory status estimation based on hematologic test results might be used to overcome clinical challenges in cases with limited laboratory equipment availability.