LOINCActiveBoth

LOINC Code 93978-5: Complement C4.functional Qn

93978-5 is a LOINC code used to identify Complement C4.functional Qn 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 C4.functional. 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 C4.functional. 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 C4.functional [Units/volume] in Serum or Plasma
  • Complement C4.functional
  • Arbitrary concentration; Beta 1 E-globulin; Comp; Complmt; HEMATOLOGY/CELL COUNTS; Pl; Plasma; Plsm; Point in time; 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 C4.functional QnComplement C4.functional [Units/volume] in Serum or PlasmaC4.functional SerPl-aCncComplement C4.functionalHEM/BCComplement C4.functional, BloodACnc

Frequently asked questions

Code details

Code93978-5
SystemLOINC
Display nameComplement C4.functional Qn
DescriptionComplement C4.functional
Short nameC4.functional SerPl-aCnc
ComponentComplement C4.functional
PropertyACnc
TimingPt
System (specimen)Ser/Plas
ScaleQn
ClassHEM/BC
Example unitsarb U/mL
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.67
Last changed2.68

Consumer names

Complement C4.functional, Blood

Part names

Complement C4.functionalACncPtSer/PlasQnArbitrary 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.

LOINC Code 93978-5 | HealthAssure