LOINC

LOINC Code 4512-0: Complement CH50 (S)

4512-0 is a LOINC code used to identify Complement CH50 (S) 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 CH50. It is commonly used with the system or sample type Ser.

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 CH50. 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: DEPRECATED

What it does not mean

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

Key facts

  • Deprecated Complement total hemolytic CH50 [Units/volume] in Serum or Plasma
  • Complement CH50
  • Comp; Complmt; HEMATOLOGY/CELL COUNTS; 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.

Common synonyms

Complement CH50 (S)Deprecated Complement total hemolytic CH50 [Units/volume] in Serum or PlasmaDeprecated CH50 Ser QnComplement CH50HEM/BCComplement CH50, Blood-

Frequently asked questions

Code details

Code4512-0
SystemLOINC
Display nameComplement CH50 (S)
DescriptionComplement CH50
Short nameDeprecated CH50 Ser Qn
ComponentComplement CH50
Property-
TimingPt
System (specimen)Ser
ScaleQn
ClassHEM/BC
StatusDEPRECATED

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0
Last changed2.66

Consumer names

Complement CH50, Blood

Part names

Complement CH50-PtSerQnPoint 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.

LOINC Code 4512-0 | HealthAssure