Clinical diagnosis of severe COVID-19: A derivation and validation of a prediction rule

Table 4 The proposed score rules for clinical diagnosis of severe coronavirus disease 2019

Variables	Description	Score
BMI	≥ 24	1
	≥ 27	2
Time from onset to admission	≥ 5 d	2
Fever	≥ 37.3 °C	2
	≥ 39 °C	4
Charlson index		1
P/F score	< 300	6
NLR	≥ 2	1
	≥ 4	2

BMI: Body mass index; P/F: PaO₂/FiO₂; NLR: Neutrophil/lymphocyte ratio.