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 2425-7: Histidine ammonia lyase (S) [Catalytic activity/Vol]

Name: LOINC Code 2425-7: Histidine ammonia lyase (S) [Catalytic activity/Vol]
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

2425-7 is a LOINC code used to identify Histidine ammonia lyase (S) [Catalytic activity/Vol] 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 Histidine ammonia lyase. 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 Histidine ammonia lyase. 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

Histidine ammonia lyase [Enzymatic activity/volume] in Serum
Histidine ammonia lyase
Amm; Ammon; Amon; Catalytic Concentration; Chemistry; Formiminoglutamic Acidemia; HAL; His; Histadine ammonium lyase; Histidase; Histidinemia; NH3; 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 Histidine ammonia lyase (S) [Catalytic activity/Vol] (2425-7)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

Histidine ammonia lyase (S) [Catalytic activity/Vol]Histidine ammonia lyase [Enzymatic activity/volume] in SerumHAL Ser-cCncHistidine ammonia lyaseCHEMHistidine ammonia lyase, BloodCCnc

Frequently asked questions

Code details

Code2425-7

SystemLOINC

Display nameHistidine ammonia lyase (S) [Catalytic activity/Vol]

DescriptionHistidine ammonia lyase

Short nameHAL Ser-cCnc

ComponentHistidine ammonia lyase

PropertyCCnc

TimingPt

System (specimen)Ser

ScaleQn

ClassCHEM

Example unitsarb U/L

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0

Last changed2.68

Consumer names

Histidine ammonia lyase, Blood

Part names

Histidine ammonia lyaseCCncPtSerQnCatalytic 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.