The 4C score, or the Coronavirus Clinical Characterisation Consortium score, is a clinical calculator specifically designed for patients diagnosed with COVID-19. This scoring system is used to predict the mortality risk in these patients. The 4C score takes into account various factors such as age, sex, number of comorbidities, respiratory rate, peripheral oxygen saturation, Glasgow Coma Scale, urea level, and C-reactive protein level. The clinical utility of this calculator is to assist healthcare professionals in making informed decisions about the level of care required for a patient, including the need for hospitalization, intensive care, or ventilator support. It can also help in prioritizing patients in situations where resources are limited. The 4C score is not applicable to patients without a confirmed diagnosis of COVID-19 or those with incomplete clinical data.

Coronavirus Clinical Characterisation Consortium score for COVID-19 mortality (4C score)

# Criteria
 ## Age, years
A. < 50 (+0)
B. 50-59 (+2)
C. 60-69 (+4)
D. 70-79 (+6)
E. >= 80 (+7)
## Sex at birth
F. Female (+0)
G. Male (+1)
## Number of comorbidities
H. 0 (+0)
I. 1 (+1)
J. >= 2 (+2)
## Respiratory rate, breaths/min
K. < 20 (+0)
L. 20-29 (+1)
M. >= 30 (+2)
## Peripheral oxygen saturation on room air, %
N. >= 92 (+0)
O. < 92 (+2)
## Glasgow Coma Scale score
P. 15 (+0)
Q. < 15 (+2)
## Blood urea nitrogen, mg/dL
R. < 19.6 (+0)
S. 19.6-39.2 (+1)
T. > 39.2 (+3)
## C-reactive protein, mg/L
U. < 50 (+0)
V. 50-99 (+1)
W. >= 100 (+2)

# Conditions
- score <= 3
- score <= 8
- score <= 14
- score >= 15
- score == 0

Risk stratification of patients admitted to hospital with covid-19 using the ISARIC WHO Clinical Characterisation Protocol: development and validation of the 4C Mortality Score.