LOINCActiveBoth

LOINC Code 28003-2: Sodium/Potassium [Molar ratio]

28003-2 is a LOINC code used to identify Sodium/Potassium [Molar ratio] in laboratory and clinical observation data. You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges. LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Sodium/Potassium. It is commonly used with the system or sample type Ser/Plas.

Reviewed by HealthAssure Clinical TeamUpdated 25 May 2026

What is this code?

LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Sodium/Potassium. It is commonly used with the system or sample type Ser/Plas.

When is it used?

  • Used in lab systems, EHRs, and clinical data exchange.
  • May identify a test, observation, survey item, or clinical document request rather than a diagnosis.
  • Status: ACTIVE
  • Order vs observation: Both

What it does not mean

  • The code identifies the observation or test, not the actual result.

Key facts

  • Sodium/Potassium [Molar ratio] in Serum or Plasma
  • Sodium/Potassium
  • Chemistry; k; K+; Na; Na+; Pl; Plasma; Plsm; Point in time; Potass; QNT; Quan; Quant; Quantitative; Random; Scrto; SerP; SerPl; SerPlas; Serum; Serum or plasma; SR; Substance concentration ratio; Substance ratio

Where you may see this code

You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges.

Common synonyms

Sodium/Potassium [Molar ratio]Sodium/Potassium [Molar ratio] in Serum or PlasmaSodium/Potassium SerPl-sRtoSodium/PotassiumCHEMSodium/Potassium, BloodSRto

Frequently asked questions

Code details

Code28003-2
SystemLOINC
Display nameSodium/Potassium [Molar ratio]
DescriptionSodium/Potassium
Short nameSodium/Potassium SerPl-sRto
ComponentSodium/Potassium
PropertySRto
TimingPt
System (specimen)Ser/Plas
ScaleQn
ClassCHEM
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.00
Last changed2.42

Consumer names

Sodium/Potassium, Blood

Part names

Sodium/PotassiumSRtoPtSer/PlasQnSubstance RatioPoint in time (spot)Serum or Plasma

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from LOINC. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

LOINC Code 28003-2 | HealthAssure