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 51820-9: L. monocytogenes IgG IA Qn (S)

Name: LOINC Code 51820-9: L. monocytogenes IgG IA Qn (S)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:35.573Z

51820-9 is a LOINC code used to identify L. monocytogenes IgG IA Qn (S) 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 Listeria monocytogenes Ab.IgG. It is commonly used with the system or sample type Ser.

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 Listeria monocytogenes Ab.IgG. It is commonly used with the system or sample type Ser.

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

What it does not mean

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

Key facts

Listeria monocytogenes IgG Ab [Units/volume] in Serum by Immunoassay
Listeria monocytogenes Ab.IgG
ABS; Aby; Antby; Anti; Antibodies; Antibody; Arbitrary concentration; Autoantibodies; Autoantibody; EIA; ELFA; ELISA; Enzyme immunoassay; IAA; ID; Immune globulin G; Immunoglobulin G; Infectious Disease; InfectiousDisease; L monocytog; L monocytogenes; Listeriosis; MEIA; Microbiology; Point in time; QNT; Quan; Quant; Quantitative; Random; Serum; SR; SUDS

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

L. monocytogenes IgG IA Qn (S)Listeria monocytogenes IgG Ab [Units/volume] in Serum by ImmunoassayL monocytog IgG Ser IA-aCncListeria monocytogenes Ab.IgGMICROListeria monocytogenes IgG antibody, BloodACnc

Frequently asked questions

Code details

Code51820-9

SystemLOINC

Display nameL. monocytogenes IgG IA Qn (S)

DescriptionListeria monocytogenes Ab.IgG

Short nameL monocytog IgG Ser IA-aCnc

ComponentListeria monocytogenes Ab.IgG

PropertyACnc

TimingPt

System (specimen)Ser

ScaleQn

MethodIA

ClassMICRO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.24

Last changed2.69

Consumer names

Listeria monocytogenes IgG antibody, Blood

Part names

Listeria monocytogenes Ab.IgGACncPtSerQnIAListeria monocytogenes IgGArbitrary ConcentrationPoint in time (spot)SerumImmunoassay

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.