Table .

Predictive criteria for cytokine storm in COVID-19 proposed by Caricchio et al. (2021)*.

Entry criteria (must be all met)	Cut-off values	Comments
• +Signs/symptoms of COVID-19 • ±RT-PCR positive for COVID-19 • +GGO by HRCT (or chest X-ray) • Ferritin • C-reactive protein	>250 ng/mL>4.6mg/dL	RT-PCR positivity was not mandatory due to the high percentage of false negatives (15%). Ferritin and CRP appeared as strong indicators of acute inflammation in COVID-CS**.
AND (one variable from each cluster)
Cluster I Albumin Lymphocyte (%)Neutrophil(absolute)	<2.8 g/dL10.211.4 K/mm3	Neutrophils and monocytes were found to be significantly increased in COVID-CS cases, suggesting an active role of innate immunity in COVID-CS. On the other hand, lymphocytes declined nearly to half of the lower normal limit, suggesting that adaptive immunity in COVID-CS was functionally depleted. Some authors suggested additionally parameters such as NLR, MLR***.
Cluster II ALT AST D-dimers LDH Troponin I	>60 U/L>87 U/L>4,930 ng/mL>416 U/L>1.09 ng/mL	ALT and AST indicative of liver cell damage were elevated to nearly twice higher normal limit; Six times higher levels of D-dimers implicated endothelial damage and thrombosis formation. Increased LDH was a sign of cell death, while moderately elevated troponin levels suggested damage of cardiovascular system.
Cluster III Anion gap ChloridePotassium BUN:creatinine ratio	<6.8>106 mmol/L >4.9 mmol/L >29 ratio	These results suggested a prerenal imbalance and kidney damage. Taken together, they reflected systemic tissue damage affecting many organs in COVID-CS.