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  COVID-19 and the Systemic Immune-Inflammation Index (SII)

Absolute Neutrophil Count  
Platelet Count  
Absolute Lymphocyte Count  

Decimal Precision  

Include literature references: Yes   No

  SII Interpretation

<=618.8: Lower criticality risk
>618.8: Higher criticality risk


  • 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.
  • The SII should be calculated from blood counts at the time of hospital admission.
  • For this calculation, note that the platelet count unit of measure is different from the white blood cell count units of measure.
  • Subjects with an SII >618.8 had a 4.7 times higher mortality. This cut-off had sensitivity of 80% and specificity of 61.5%.[1]

Equations used
SII = AbsoluteNeutrophilCount * PlateletCount / AbsoluteLymphocyteCount


  1. Karaaslan T, Karaaslan E. Predictive Value of Systemic Immune-inflammation Index in Determining Mortality in COVID-19 Patients. J Crit Care Med (Targu Mures). 2022 Aug 12;8(3):156-164. PubMed ID: 36062039 PubMed Logo

Associated Logical Observation Identifiers Names and Codes [LOINC]
Parameter LOINC's and Suggested Units
Absolute Neutrophil Count 751-8 : 10^3/microL      26499-4 : 10^3/microL      753-4 : 10^3/microL      
Platelet Count 777-3 : x10^9/L      26515-7 : x10(3)/mcL      
Absolute Lymphocyte Count 731-0 : x10^3/microL      26474-7 : x10^3/microL      732-8 : x10^3/microL      

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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