Complete Blood-count-based Inflammatory Score (CBCS) of COVID-19 Patients at Tertiary Care Center

Inflammation is a significant factor driving the rise of multiple cases of viral pneumonia, including COVID-19 infection. Peripheral white blood cells (WBCs), the neutrophil (NEU)-to-lymphocyte (LYM) ratio (NLR), the platelet-to-lymphocyte (PLR) ratio, and hemoglobin (Hb) are markers of systematic inflammatory reaction and often predict disease severity.

The current study intended to examine the prognostic importance of hemoglobin (Hb), total leukocyte count (TLC), absolute neutrophile count (ANC), absolute lymphocyte count (ALC), NLR, d-NLR [derived NLR = ANC/(WBC-ANC)], absolute platelet count (APC), and PLR, based on complete blood counts (CBCs) for COVID-19 patients.

The research team designed a retrospective that was conducted between March 27 and June 5, 2020, after the first COVID-19 case was reported in Ajmer, Rajasthan, India on March 27.

The study took place at Jawaharlal Nehru (JLN) Medical College in Ajmer, Rajasthan, India.

The study included 364 participants who were all COVID-positive patients who came to the hospital during the study's period, including patients from various age groups and of both genders.

Using the results of the CBC, the research team measured: (1) Hb in g/dl, (2) ANC, (3) ALC, and (4) APC. The neutrophil-lymphocyte ratio (NLR) and the platelet-lymphocyte ratio (PLR) were calculated from measurements of the levels of the circulating biomarkers, as cells × 103/μl.

For participants who were severely symptomatic, the mean age was 57.86 ± 8.92. Males were more likely to experience severe symptoms. Participants' Hb values were significantly different between groups, and TLC, ANC, NLR, d-NLR, and PLR were highest in the severely symptomatic group and lowest in the asymptomatic group. NLR was positively associated with a risk of COVID-19 pneumonia, while Hb was negatively associated with development of pneumonia.

Disease severity and age are independent predictors of poor outcomes. The NLR should be used as a routine blood test that can help in the diagnosis of disease severity in COVID-19. NLR is very simple tool that can be used as a fast and low-cost test that is easily available, even in small centers where the facilities for other tests, such as tests of LDH, CRP, and IL-6, and high resolution CT scans aren't available. Thus, NLR can be used as single independent predictor of COVID-19 disease severity.