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.

LOINCActiveBoth

LOINC Code 31821-2: Equine influenza virus A1 Ag Qn (Specimen)

Name: LOINC Code 31821-2: Equine influenza virus A1 Ag Qn (Specimen)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:18.899Z

31821-2 is a LOINC code used to identify Equine influenza virus A1 Ag Qn (Specimen) 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 Equine influenza virus A1 Ag. It is commonly used with the system or sample type XXX.

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 Equine influenza virus A1 Ag. It is commonly used with the system or sample type XXX.

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

Equine influenza virus A1 Ag [Units/volume] in Specimen
Equine influenza virus A1 Ag
Antigen; Antigens; Arbitrary concentration; EIV; EIV A1; Equin; Equine influenza; FLUV; ID; Infectious Disease; InfectiousDisease; Influ; Microbiology; Misc; Miscellaneous; Other; Point in time; QNT; Quan; Quant; Quantitative; Random; Spec; To be specified in another part of the message; Unspecified; Vet; Veterinary

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

Equine influenza virus A1 Ag Qn (Specimen)Equine influenza virus A1 Ag [Units/volume] in SpecimenEIV A1 Ag Spec-aCncEquine influenza virus A1 AgMICROEquine influenza virus A1 antigen, SpecimenACnc

Frequently asked questions

Code details

Code31821-2

SystemLOINC

Display nameEquine influenza virus A1 Ag Qn (Specimen)

DescriptionEquine influenza virus A1 Ag

Short nameEIV A1 Ag Spec-aCnc

ComponentEquine influenza virus A1 Ag

PropertyACnc

TimingPt

System (specimen)XXX

ScaleQn

ClassMICRO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.07

Last changed2.69

Consumer names

Equine influenza virus A1 antigen, Specimen

Part names

Equine influenza virus A1 AgACncPtXXXQnArbitrary ConcentrationPoint in time (spot)

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.