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 49637-2: HTT gene allele 1.CAG repeats Molgen (Bld/Tiss) [Entitic number]

Name: LOINC Code 49637-2: HTT gene allele 1.CAG repeats Molgen (Bld/Tiss) [Entitic number]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:33.942Z

49637-2 is a LOINC code used to identify HTT gene allele 1.CAG repeats Molgen (Bld/Tiss) [Entitic number] 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 HTT gene allele 1.CAG repeats. It is commonly used with the system or sample type Bld/Tiss.

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 HTT gene allele 1.CAG repeats. It is commonly used with the system or sample type Bld/Tiss.

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: Molgen

What it does not mean

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

Key facts

HTT gene allele 1.CAG repeats [Entitic number] in Blood or Tissue by Molecular genetics method
HTT gene allele 1.CAG repeats
5HTT; 5-HTT; 5-HTTLPR; Blood; Entitic; Entitic number; Genetics; HD gene; Heredity; Heritable; hSERT; HTT; HTT allele 1 CAG Rpt; huntingtin; Huntington chorea; Huntington disease; Huntington's disease; i; Inherited; IT15; Molecular genetics; Molecular pathology; MOLPATH; MOLPATH.NUCREPEAT; OCD1; PCR; Point in time; QNT; Quan; Quant; Quantitative; Random; Repeat; SERT; SERT1; solute carrier family 6 (neurotransmitter transporter), member 4; Tissue; Tissue, unspecified; WB; Whole blood; Whole blood or Tissue

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

HTT gene allele 1.CAG repeats Molgen (Bld/Tiss) [Entitic number]HTT gene allele 1.CAG repeats [Entitic number] in Blood or Tissue by Molecular genetics methodHTT allele 1 CAG Rpt EntNum Bld/THTT gene allele 1.CAG repeatsMOLPATH.NUCREPEATHTT gene Allele 1 CAG Repeats, Blood or tissue specimenEntNum

Frequently asked questions

Code details

Code49637-2

SystemLOINC

Display nameHTT gene allele 1.CAG repeats Molgen (Bld/Tiss) [Entitic number]

DescriptionHTT gene allele 1.CAG repeats

Short nameHTT allele 1 CAG Rpt EntNum Bld/T

ComponentHTT gene allele 1.CAG repeats

PropertyEntNum

TimingPt

System (specimen)Bld/Tiss

ScaleQn

MethodMolgen

ClassMOLPATH.NUCREPEAT

Example unitsCAG Repeats

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.22

Last changed2.73

Consumer names

HTT gene Allele 1 CAG Repeats, Blood or tissue specimen

Part names

HTT gene allele 1.CAG repeatsEntNumPtBld/TissQnMolgenEntitic numberPoint in time (spot)Blood or TissueMolecular genetics

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.