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 4503-9: Complement C4b binding protein [Mass/Vol]

Name: LOINC Code 4503-9: Complement C4b binding protein [Mass/Vol]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:30.175Z

4503-9 is a LOINC code used to identify Complement C4b binding protein [Mass/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 Complement C4b binding protein. It is commonly used with the system or sample type Ser/Plas.

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 Complement C4b binding protein. 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: Both

What it does not mean

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

Key facts

Complement C4b binding protein [Mass/volume] in Serum or Plasma
Complement C4b binding protein
Bind; C4b BP; C4bBP; C4bp; Comp; Complmt; HEMATOLOGY/CELL COUNTS; Level; Mass concentration; Pl; Plasma; Plsm; Point in time; PR; Prot; QNT; Quan; Quant; Quantitative; Random; 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

Complement C4b binding protein [Mass/Vol]Complement C4b binding protein [Mass/volume] in Serum or PlasmaC4b BP SerPl-mCncComplement C4b binding proteinHEM/BCComplement C4b Binding Protein, BloodMCnc

Frequently asked questions

Code details

Code4503-9

SystemLOINC

Display nameComplement C4b binding protein [Mass/Vol]

DescriptionComplement C4b binding protein

Short nameC4b BP SerPl-mCnc

ComponentComplement C4b binding protein

PropertyMCnc

TimingPt

System (specimen)Ser/Plas

ScaleQn

ClassHEM/BC

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0

Last changed2.73

Consumer names

Complement C4b Binding Protein, Blood

Part names

Complement C4b binding proteinMCncPtSer/PlasQnMass ConcentrationPoint 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.