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 55804-9: Leukocyte phosphatase Ql (WBC)

Name: LOINC Code 55804-9: Leukocyte phosphatase Ql (WBC)
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

55804-9 is a LOINC code used to identify Leukocyte phosphatase Ql (WBC) 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 Phosphatase.leukocyte. It is commonly used with the system or sample type WBC.

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 Phosphatase.leukocyte. It is commonly used with the system or sample type WBC.

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

Leukocyte phosphatase [Presence] in Leukocytes
Phosphatase.leukocyte
HEMATOLOGY/CELL COUNTS; LAP; Leuc; Leuk; Leukocyte alkaline phosphatase; Leukocytes; Lkcs; NAT; Neutrophil alkaline phosphatase; Ordinal; Phos; Phosphtase; Point in time; PR; QL; Qual; Qualitative; Random; Screen; WBC; WBCs; White blood cell; White blood cells

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 Leukocyte phosphatase Ql (WBC) (55804-9)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

Leukocyte phosphatase Ql (WBC)Leukocyte phosphatase [Presence] in LeukocytesLAP WBC QlPhosphatase.leukocyteHEM/BCLeukocyte phosphatase, White blood cellsPrThr

Frequently asked questions

Code details

Code55804-9

SystemLOINC

Display nameLeukocyte phosphatase Ql (WBC)

DescriptionPhosphatase.leukocyte

Short nameLAP WBC Ql

ComponentPhosphatase.leukocyte

PropertyPrThr

TimingPt

System (specimen)WBC

ScaleOrd

ClassHEM/BC

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.29

Last changed2.73

Consumer names

Leukocyte phosphatase, White blood cells

Part names

Phosphatase.leukocytePrThrPtWBCOrdLeukocyte phosphatasePresence or ThresholdPoint in time (spot)White blood cells

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.