An analysis of hematological, coagulation and biochemical markers in COVID-19 disease and their association with clinical severity and mortality: an Indian outlook.

Background: The "cytokine storm" (CS) in COVID-19 leads to the worst stage of illness which can be controlled only with timely intervention. There is an urgent need to identify laboratory markers of disease progression for optimum allocation of resources in developing countries like India.

Methods: A cross-sectional study was conducted on 100 COVID-19 positive patients over two months. The cases were sub-classified based on disease severity into mild to moderate (n=61), severe (n=26) and very severe (n=13) and into survivors (n=85) and non-survivors (n=15) based on survivor status. These patients were tested for hematological parameters (total blood lymphocyte counts, NLR, PLR, platelet indices etc.), coagulation markers (D-dimer, fibrin degradation products (FDP), fibrinogen etc.) and biochemical markers (LDH, ferritin, IL-6, procalcitonin, hs-CRP).

Results: Statistically significant differences were observed in hematological variables (ANC, NLR and ESR), coagulation parameters (D-dimer, FDP, fibrinogen and thrombin time) and biochemical markers (LDH, ferritin, IL-6, procalcitonin and hs-CRP) with regard to subcategories based of disease severity as well as survivor status. There was strong correlation between NLR, D-dimer, IL-6, procalcitonin and ferritin. IL-6 emerged as the single best marker of disease severity (AUC: 0.997, P=0.00), however procalcitonin, LDH, D-dimer, FDP and NLR could also predict severe disease with a good sensitivity and specificity.

Conclusion: To conclude, study demonstrates a plethora of biomarkers which could be utilized to accurately identify the hyperinflammation and tissue damage reminiscent of cytokine storm in COVID-19 patients so that timely, safe, and effective therapies can be administered to prevent progression and potentially reduce mortality.