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 49189-4: C. diphtheriae toxin IgG Qn (S)

Name: LOINC Code 49189-4: C. diphtheriae toxin IgG Qn (S)
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

49189-4 is a LOINC code used to identify C. diphtheriae toxin IgG 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 Corynebacterium diphtheriae toxin Ab.IgG. It is commonly used with the system or sample type Ser.

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 Corynebacterium diphtheriae toxin 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

What it does not mean

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

Key facts

Corynebacterium diphtheriae toxin IgG Ab [Units/volume] in Serum
Corynebacterium diphtheriae toxin Ab.IgG
ABS; Aby; Antby; Anti; Antibodies; Antibody; Arbitrary concentration; Autoantibodies; Autoantibody; C diphtheriae; C diphtheriae Tox; Diphtheria; Diptheria; ID; Immune globulin G; Immunoglobulin G; Infectious Disease; InfectiousDisease; Microbiology; Point in time; QNT; Quan; Quant; Quantitative; Random; Serum; SR

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.

Related SNOMED CT concepts

705114005SNOMED CT mapping for C. diphtheriae toxin IgG Qn (S) (49189-4)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

C. diphtheriae toxin IgG Qn (S)Corynebacterium diphtheriae toxin IgG Ab [Units/volume] in SerumC diphtheriae Tox IgG Ser-aCncCorynebacterium diphtheriae toxin Ab.IgGMICROCorynebacterium diphtheriae toxin IgG antibody, BloodACnc

Frequently asked questions

Code details

Code49189-4

SystemLOINC

Display nameC. diphtheriae toxin IgG Qn (S)

DescriptionCorynebacterium diphtheriae toxin Ab.IgG

Short nameC diphtheriae Tox IgG Ser-aCnc

ComponentCorynebacterium diphtheriae toxin Ab.IgG

PropertyACnc

TimingPt

System (specimen)Ser

ScaleQn

ClassMICRO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.21

Last changed2.69

Consumer names

Corynebacterium diphtheriae toxin IgG antibody, Blood

Part names

Corynebacterium diphtheriae toxin Ab.IgGACncPtSerQnCorynebacterium diphtheriae toxin IgGArbitrary ConcentrationPoint in time (spot)Serum

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.