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  COVID-19 ISARIC C4 Score

 
Input
 
Age  
Sex Female (0)

Male (1)
Comorbidities  
Respiratory Rate  
O2Sat  
Glasgow Coma Scale  
Urea  
CRP  

 
Result
 
 
C4 Score  
 

 
     
 
Include literature references: Yes   No

 
  C4 Score and In-hospital Mortality Prediction

 
0 to 3 points: Low risk (1.2 to1.7% mortality)
4 to 8 points: Intermediate risk (9.1 to 9.9% mortality)
9 to 14 points: High risk (31.4 to 34.9% mortality)
15 to 21 points: Very High risk (61.5 to 66.2% mortality)

 
 

 
Notes
  • In this calculator, mcg is the abbreviation for micrograms.
  • This calculator represents findings from the literature referenced below. It is important to understand that these findings may not be representative of the experience in your local healthcare system.
  • O2Sat is measrued on room air.
  • ISARIC: International Severe Acute Respiratory and emerging Infections Consortium; 4C: Coronavirus Clinical Characterisation Consortium.

 
Equations used
 
C4Score = AgeFactor + Sex + ComorbiditiesFactor + RespRateFactor + O2SatFactor +GCSFactor + UreaFactor + CRPFactor

 

 
Calculation Details and Variables
  • AgeFactor is assigned values by this ordered logic:
    • If Age ≥80 yr AgeFactor = 7
    • Else if Age ≥70 yr AgeFactor = 6
    • Else if Age ≥60 yr AgeFactor = 4
    • Else if Age ≥50 yr AgeFactor = 2
    • Else AgeFactor = 0.
  • Equation parameters such as Sex, have two or more discrete values that may be used in the calculation. The numbers in the parentheses, e.g. (0), represent the values that will be used.
  • ComorbiditiesFactor is assigned values by this ordered logic:
    • If Comorbidities ≥2 number ComorbiditiesFactor = 2
    • Else if Comorbidities ≥1 number ComorbiditiesFactor = 1
    • Else ComorbiditiesFactor = 0.
  • RespRateFactor is assigned values by this ordered logic:
    • If Respiratory Rate ≥30 breaths/min RespRateFactor = 2
    • Else if Respiratory Rate ≥20 breaths/min RespRateFactor = 1
    • Else RespRateFactor = 0.
  • O2SatFactor is assigned values by this ordered logic:
    • If O2Sat <92 % O2SatFactor = 2
    • Else O2SatFactor = 0.
  • GCSFactor is assigned values by this ordered logic:
    • If Glasgow Coma Scale <15 points GCSFactor = 2
    • Else GCSFactor = 0.
  • UreaFactor is assigned values by this ordered logic:
    • If Urea >14 mmol/L UreaFactor = 3
    • Else if Urea ≥7 mmol/L UreaFactor = 1
    • Else UreaFactor = 0.
  • CRPFactor is assigned values by this ordered logic:
    • If CRP ≥100 mg/L CRPFactor = 2
    • Else if CRP ≥50 mg/L CRPFactor = 1
    • Else CRPFactor = 0.

 
References
  1. Knight SR, Ho A, Pius R, et al. 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. BMJ. 2020 Sep 9;370:m3339. PubMed ID: 32907855 PubMed Logo
  2. Aletreby WT, Mumtaz SA, Shahzad SA, et al. External Validation of 4C ISARIC Mortality Score in Critically ill COVID-19 Patients from Saudi Arabia. Saudi J Med Med Sci. 2022 Jan-Apr;10(1):19-24. PubMed ID: 35283713 PubMed Logo

 
Associated Medical Subject Headings [MeSH]
 
         80 and over,   Aged,   Betacoronavirus,   COVID-19,   Clinical Protocols,   Cohort Studies,   Coronavirus Infections,   Female,   Hospital Mortality,   Hospitalization,   Humans,   Male,   Middle Aged,   Pandemics,   Pneumonia,   Predictive Value of Tests,   ROC Curve,   Risk Assessment,   SARS-CoV-2,   Survival Rate,   United Kingdom,   Viral

 
Associated Logical Observation Identifiers Names and Codes [LOINC]
 
Parameter LOINC's and Suggested Units
Age 21612-7 : yr      21612-7 : yr      21612-7 : years      30525-0 : Years old      30525-0 : yr      30525-0 : years      
Respiratory Rate 9303-9 : breaths/min      9279-1 : breaths/min      76170-0 : breaths/min      19840-8 : breaths/min      
O2Sat 2708-6 : %      2713-6 : %      51733-4 : %      59408-5 : %      
Glasgow Coma Scale 9269-2 : score      
Urea 3094-0 : mg/dL      6299-2 : mg/dL      14937-7 : mmol/L      59570-2 : mmol/L      
CRP 1988-5 : mg/L      48421-2 : mg/L      76485-2 : nmol/L      

 
This material contains content from LOINC® (http://loinc.org). The LOINC table, LOINC codes, and LOINC panels and forms file are copyright © 1995-2014, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and available at no cost under the license at http://loinc.org/terms-of-use.

 

 
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