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 91821-9: Adenovirus Ag IA.rapid Ql (Upper resp)

Name: LOINC Code 91821-9: Adenovirus Ag IA.rapid Ql (Upper resp)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T09:00:21.442Z

91821-9 is a LOINC code used to identify Adenovirus Ag IA.rapid Ql (Upper resp) 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 Adenovirus Ag. It is commonly used with the system or sample type Respiratory system specimen.upper.

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 Adenovirus Ag. It is commonly used with the system or sample type Respiratory system specimen.upper.

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
Method: IA.rapid

What it does not mean

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

Key facts

Adenovirus Ag [Presence] in Upper respiratory specimen by Rapid immunoassay
Adenovirus Ag
Adeno virus; Antigen; Antigens; Breathing; EIA; ELFA; ELISA; Enzyme immunoassay; HAdV; IAA; Lungs; MEIA; Microbiology; Ordinal; Point in time; PR; QL; Qual; Qualitative; Random; RS; Screen; Spec; SUDS; Up; Upper resp

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

Adenovirus Ag IA.rapid Ql (Upper resp)Adenovirus Ag [Presence] in Upper respiratory specimen by Rapid immunoassayHAdV Ag Upper resp Ql IA.rapidAdenovirus AgMICROAdenovirus antigen, Upper respiratoryPrThr

Frequently asked questions

Code details

Code91821-9

SystemLOINC

Display nameAdenovirus Ag IA.rapid Ql (Upper resp)

DescriptionAdenovirus Ag

Short nameHAdV Ag Upper resp Ql IA.rapid

ComponentAdenovirus Ag

PropertyPrThr

TimingPt

System (specimen)Respiratory system specimen.upper

ScaleOrd

MethodIA.rapid

ClassMICRO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.66

Last changed2.77

Consumer names

Adenovirus antigen, Upper respiratory

Part names

Adenovirus AgPrThrPtRespiratory system specimen.upperOrdIA.rapidPresence or ThresholdPoint in time (spot)Upper respiratory specimenRapid immunoassay

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.