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  COVID-19 Quick Severity Index (qCSI)

Respiratory Rate  
O2 Saturation  
Oxygen Flow Rate  

Important: Inputs must be complete to perform calculation.

Decimal Precision  

Include literature references: Yes   No

  qCSI Interpretation

0 to 3 points: 4% risk of critical illness
4 to 6 points: 30% risk of critical illness
7 to 9 points: 44% risk of critical illness
10 to 12 points: 57% risk of critical illness


  • 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.

Equations used
qCSI = RRFactor + O2SatFactor + O2FlowFactor


Calculation Details and Variables
  • RRFactor is assigned values by this ordered logic:
    • If Respiratory Rate >28 breaths/min RRFactor = 2
    • Else if Respiratory Rate ≥23 breaths/min RRFactor = 1
    • Else RRFactor = 0.
  • O2SatFactor is assigned values by this ordered logic:
    • If O2 Saturation ≤88 % O2SatFactor = 5
    • Else if O2 Saturation ≤92 % O2SatFactor = 2
    • Else O2SatFactor = 0.
  • O2FlowFactor is assigned values by this ordered logic:
    • If Oxygen Flow Rate ≤2 L/min O2FlowFactor = 0
    • Else if Oxygen Flow Rate ≤4 L/min O2FlowFactor = 4
    • Else O2FlowFactor = 5.

  1. Haimovich AD, Ravindra NG, Stoytchev S, et al. Development and Validation of the Quick COVID-19 Severity Index: A Prognostic Tool for Early Clinical Decompensation. Ann Emerg Med. 2020 Oct;76(4):442-453. PubMed ID: 33012378 PubMed Logo

Associated Medical Subject Headings [MeSH]
         Adolescent,   Adult,   Aged,   Betacoronavirus,   COVID-19,   COVID-19 Testing,   Clinical Laboratory Techniques,   Coronavirus Infections,   Emergency Service,   Female,   Hospital,   Humans,   Male,   Middle Aged,   Oxygen Inhalation Therapy,   Pandemics,   Pneumonia,   Respiratory Insufficiency,   Retrospective Studies,   Risk Assessment,   SARS-CoV-2,   Severity of Illness Index,   Viral,   Young Adult

Associated Logical Observation Identifiers Names and Codes [LOINC]
Parameter LOINC's and Suggested Units
Respiratory Rate 9303-9 : breaths/min      9279-1 : breaths/min      76170-0 : breaths/min      19840-8 : breaths/min      
O2 Saturation 2708-6 : %      2713-6 : %      51733-4 : %      59408-5 : %      

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.

Associated ICD10-CM Codes
   J12.9Viral pneumonia, unspecified
   J12.89Other viral pneumonia


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