THE IMPORTANCE OF A CLINICAL BLOOD TEST IN MANAGING THE RISKS OF CORONAVIRUS INFECTION: THE EXPERIENCE OF COVID-19

BACKGROUND: The causative agent of coronavirus infection COVID-19 continues to circulate among the population and cause severe forms. A successful outcome depends on the correct assessment of the severity of patients in the early stages of the disease, timely hospitalization and competent correction of the therapy. The general blood test performed during the initial diagnosis proved to be one of the most significant in assessing the severity of the patient.

AIM: To assess quantitative and calculated indicators of the general blood test depending on the severity of patient's illness upon admission to the hospital and in dynamics, as well as to identify the predictors of an unfavorable outcome of the disease.

METHODS: An one-stage retrospective analysis of the medical records of 122 patients admitted from March to July 2021 to the N.V. Sklifosovsky Research Institute for Emergency Medicine with a confirmed diagnosis of "COVID-19, severe course" no later than 3 days from the onset of the disease was carried out. Depending on the outcome of the disease all patients were divided into two groups: 1 – survived, 2 – died. Venous blood was taken from all patients upon admission and on the seventh day of hospital stay, followed by testing on an Advia 2120i hematology analyzer (Siemens, USA). Additionally, the neutrophil-lymphocyte (NEU/LYM) and platelet-lymphocyte (PLT/LYM) ratios, as well as the systemic inflammation index (SII) were calculated. Quantitative and calculation analysis of clinical blood test parameters was performed in comparison with reference values of the norm and between two formed groups in the dynamics.

RESULTS: The patients in group 2 compared to group 1 had higher absolute values of leukocytes with relative neutrophilia, lymphopenia and eosinopenia at all observation periods. The platelet count had multidirectional dynamics: in group 1 there was a tendency for its increase on day 7, in group 2 – a stable decrease of this parameter. The ESR values were comparable in both groups at the early stages of the disease, sharply increasing by day 7 in patients of group 2 and decreasing in group 1. The most indicative were NEU/LYM, PLT/LYM and SII ratios, the values of these parameters had statistically significant differences between themselves, and dominated in the patients of group 2 at all observation stages.

CONCLUSION: The lymphocyte count and neutrophil-lymphocyte ratio are early sensitive bioindicators of the infectious process’s severity, the effectiveness of the therapy and the prognosis of COVID-19 outcome.