LOINCActiveObservation

LOINC Code 2559-3: Leucine Ql

2559-3 is a LOINC code used to identify Leucine Ql 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 Leucine. It is commonly used with the system or sample type Ser/Plas.

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 Leucine. It is commonly used with the system or sample type Ser/Plas.

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: Observation

What it does not mean

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

Key facts

  • Leucine [Presence] in Serum or Plasma
  • Leucine
  • Chemistry; Leu; Ordinal; Pl; Plasma; Plsm; Point in time; PR; QL; Qual; Qualitative; Random; Screen; SerP; SerPl; SerPlas; Serum; Serum or plasma; 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.

Common synonyms

Leucine QlLeucine [Presence] in Serum or PlasmaLeucine SerPl QlLeucineCHEMLeucine, BloodPrThr

Frequently asked questions

Code details

Code2559-3
SystemLOINC
Display nameLeucine Ql
DescriptionLeucine
Short nameLeucine SerPl Ql
ComponentLeucine
PropertyPrThr
TimingPt
System (specimen)Ser/Plas
ScaleOrd
ClassCHEM
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0
Last changed2.73

Consumer names

Leucine, Blood

Part names

LeucinePrThrPtSer/PlasOrdPresence or ThresholdPoint in time (spot)Serum or Plasma

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.

LOINC Code 2559-3 | HealthAssure