Ions and electrolyte substances

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Overview

Previously, SNOMED CT represented ions and electrolytes as separate concepts. Although the two terms are subtly different, there is considerable overlap in their definitions, and they seem to be used interchangeably in medicine. The Substances Redesign Project Group considered this issue and determined the following:

• Ions should be modeled as child concepts of the substance.

• A second parent (in addition to X (substance)), that indicates the concept is an ionized substance, should be modeled.

  • Use a descendant of 86355000 |Electrolyte (substance)| as the additional parent. (<<86355000 |Electrolyte (substance)| are used in LOINC term expression associations.)

• Non-Ionized/Non-Ionised substances should not be created.

Pattern:

• X ion (substance)

For example,

• Ferric ion (substance)

Pattern:

• X ion

For example,

• Ferric ion

Pattern: "Ionized X" and "X electrolyte" Add "Ionised X" as GB synonym.

For example,

• Ionised fluorine

• Ionized fluorine

• Fluoride electrolyte

Where an element can exist with more than one level of oxidation, for example, iron can exist in either the ferric (Fe³⁺) or ferrous (Fe ²⁺) ionization states, the synonyms "Ionised X" and "Ionized X" should not be added since they are ambiguous.

The following illustrates the Stated andInferred view:

The following illustrates the hierarchy view: