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  COVID-19 CALL Score

Comorbidity No (1)

Yes (4)
Absolute Lymphocyte Count  

Important: Inputs must be complete to perform calculation.

CALL Score  

  CALL Score Interpretation

4 to 6 points: Low risk of disease progression
7 to 13 points: High risk of disease progression


  Data action

Include literature references: Yes   No

  • 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.
  • CALL: Comorbidity, Age, Lymphocyte, and LDH.
  • Comorbidities include HIV, Chronic lung disease, cardiovascular disease, diabetes, and hypertension.
  • The follow-up study in Turkey[2] showed less predictive power (ROC-AUC 0.59) than the original Chinese study (ROC-AUC 0.91).[1]

Equations used
CALLScore = Comorbidity + AgeFactor + LymphocyteFactor + LDHFactor


Calculation Details and Variables
  • Equation parameters such as Comorbidity, have two or more discrete values that may be used in the calculation. The numbers in the parentheses, e.g. (1), represent the values that will be used.
  • AgeFactor is assigned values by this ordered logic:
    • If Age >60 yr, AgeFactor = 3
    • Else AgeFactor = 1.
  • LymphocyteFactor is assigned values by this ordered logic:
    • If Absolute Lymphocyte Count ≤1 x10(9)/L, LymphocyteFactor = 3
    • Else LymphocyteFactor = 1.
  • LDHFactor is assigned values by this ordered logic:
    • If LDH >500 U/L, LDHFactor = 3
    • Else if LDH ≥250 U/L, LDHFactor = 2
    • Else LDHFactor = 1.

  1. Ji D, Zhang D, Xu J, et al. Prediction for Progression Risk in Patients With COVID-19 Pneumonia: The CALL Score. Clin Infect Dis. 2020 Sep 12;71(6):1393-1399. PubMed ID: 32271369 PubMed Logo
  2. Erturk Sengel B, Tukenmez Tigen E, Ilgin C, et al. Application of CALL score for prediction of progression risk in patients with COVID-19 at university hospital in Turkey. Int J Clin Pract. 2021 Jul 26:e14642. PubMed ID: 34310000 PubMed Logo

Associated Medical Subject Headings [MeSH]
         Adult,   Aged,   Betacoronavirus,   COVID-19,   China,   Clinical Decision Rules,   Coronavirus Infections,   Disease Progression,   Female,   Hospitals,   Humans,   Lymphocyte Count,   Male,   Middle Aged,   Multivariate Analysis,   Nomograms,   Pandemics,   Pneumonia,   Prognosis,   Proportional Hazards Models,   Retrospective Studies,   Risk Assessment,   Risk Factors,   SARS-CoV-2,   Severity of Illness Index,   Turkey,   University,   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      
Absolute Lymphocyte Count 731-0 : x10^3/microL      26474-7 : x10^3/microL      732-8 : x10^3/microL      
LDH 14804-9 : U/L      14805-6 : U/L      2537-9 : U/L      

This material contains content from LOINC (http://loinc.org). LOINC is copyright © 1995-2023, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license. LOINC® is a registered United States trademark of Regenstrief Institute, Inc.

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


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