What does this LOINC code represent?

This LOINC code identifies a lab observation, measurement, question, or clinical concept in a standardized format.

Is this enough to understand my test result?

No. The code identifies the test or observation, but the interpretation depends on the actual result, reference range, and clinical context.

LOINCActiveObservation

LOINC Code 49591-1: 25-hydroxyvitamin D3 and Vitamin D2 Nar [Interp]

Name: LOINC Code 49591-1: 25-hydroxyvitamin D3 and Vitamin D2 Nar [Interp]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:33.941Z

49591-1 is a LOINC code used to identify 25-hydroxyvitamin D3 and Vitamin D2 Nar [Interp] 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 Calcidiol & Calciferol. It is commonly used with the system or sample type Ser/Plas.

Reviewed by HealthAssure Clinical TeamUpdated 21 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 Calcidiol & Calciferol. 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: Observation

What it does not mean

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

Key facts

Calcidiol and Calciferol [Interpretation] in Serum or Plasma Narrative
Calcidiol & Calciferol
25(OH)D3; 25-hydroxycholecalciferol; 25-hydroxyvitamin D 3; 25-hydroxyvitamin D metabolites; 25-hydroxyvitamin D2 + D3; 25-hydroxyvitamin D3; Activated ergosterol; C28H43OH; Calciderol; Calcidiol+Calciferol; Calcifediol; Chemistry; Ercalciol; Ergocalciferol; Impression; Impression/interpretation of study; Impressions; Interp; Interpretation; Narrative; Pl; Plasma; Plsm; Point in time; Pro vitamin D; Random; Report; SerP; SerPl; SerPlas; Serum; Serum or plasma; SR; Viosterol; Vit D 1 25 hydroxy; Vit D2; Vitamin D 25 hydroxy; Vitamin D2

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

25-hydroxyvitamin D3 and Vitamin D2 Nar [Interp]Calcidiol and Calciferol [Interpretation] in Serum or Plasma NarrativeCalcidiol & Calciferol SerPl-ImpCalcidiol & CalciferolCHEMInterpretation of 25-hydroxyvitamin D3 and Vitamin D2 test result, BloodImp

Frequently asked questions

Code details

Code49591-1

SystemLOINC

Display name25-hydroxyvitamin D3 and Vitamin D2 Nar [Interp]

DescriptionCalcidiol & Calciferol

Short nameCalcidiol & Calciferol SerPl-Imp

ComponentCalcidiol & Calciferol

PropertyImp

TimingPt

System (specimen)Ser/Plas

ScaleNar

ClassCHEM

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.22

Last changed2.38

Consumer names

Interpretation of 25-hydroxyvitamin D3 and Vitamin D2 test result, Blood

Part names

Calcidiol & CalciferolImpPtSer/PlasNarCalcidiol and CalciferolImpression/interpretation of studyPoint 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.