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COVID-19 ISARIC C4 Score

 

Input
 

Age		mo yr
Sex	Female (0)
	Male (1)
Comorbidities		# count index logit none number points score
Respiratory Rate		br/min breaths/min
O2Sat		% fraction percent rate ratio
Glasgow Coma Scale		# count index logit none number points score
Urea		mg/dL mmol/L
CRP		mg/L mg/dL nmol/L

 
Result
 
Important: Inputs must be complete to perform calculation.

 

C4 Score		# count index logit none number points 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

• 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
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

 

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      35088-4 : 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.