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 1899-4: Argininosuccinate synthase (Tiss) [Catalytic activity/Mass]

Name: LOINC Code 1899-4: Argininosuccinate synthase (Tiss) [Catalytic activity/Mass]
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

1899-4 is a LOINC code used to identify Argininosuccinate synthase (Tiss) [Catalytic activity/Mass] 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 Argininosuccinate synthase. It is commonly used with the system or sample type Tiss.

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 Argininosuccinate synthase. It is commonly used with the system or sample type 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

What it does not mean

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

Key facts

Argininosuccinate synthase [Enzymatic activity/mass] in Tissue
Argininosuccinate synthase
Argininosuccinic acid; arginosuccinate; Arginosuccinic acid; ASA; ASA Synthase; Catalytic Content; Chemistry; Point in time; QNT; Quan; Quant; Quantitative; Random; Tissue; Tissue, unspecified

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 Argininosuccinate synthase (Tiss) [Catalytic activity/Mass] (1899-4)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

Argininosuccinate synthase (Tiss) [Catalytic activity/Mass]Argininosuccinate synthase [Enzymatic activity/mass] in TissueASA Synthase Tiss-cCntArgininosuccinate synthaseCHEMArgininosuccinate synthase, TissueCCnt

Frequently asked questions

Code details

Code1899-4

SystemLOINC

Display nameArgininosuccinate synthase (Tiss) [Catalytic activity/Mass]

DescriptionArgininosuccinate synthase

Short nameASA Synthase Tiss-cCnt

ComponentArgininosuccinate synthase

PropertyCCnt

TimingPt

System (specimen)Tiss

ScaleQn

ClassCHEM

Example unitsnmol/min/mg protein

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0

Last changed2.42

Consumer names

Argininosuccinate synthase, Tissue

Part names

Argininosuccinate synthaseCCntPtTissQnCatalytic ContentPoint in time (spot)Tissue and Smears

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.