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 42601-5: Immune complex.IgG C1q binding assay Qn (Syn fld)

Name: LOINC Code 42601-5: Immune complex.IgG C1q binding assay Qn (Syn fld)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:28.128Z

42601-5 is a LOINC code used to identify Immune complex.IgG C1q binding assay Qn (Syn fld) 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 Immune complex.IgG. It is commonly used with the system or sample type Synv fld.

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 Immune complex.IgG. It is commonly used with the system or sample type Synv fld.

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
Method: C1q binding assay

What it does not mean

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

Key facts

Immune complex.IgG [Units/volume] in Synovial fluid by C1q binding assay
Immune complex.IgG
Arbitrary concentration; Bind; CIC; Circulating immune complex; Compx; IC; IC IgG; Imm; Immune globulin G; Immunoglobulin G; Imun; Imune; Joint aspirate; Joint fld; Joint flu; Joint fluid; Point in time; QNT; Quan; Quant; Quantitative; Random; Serology; SF; SNV; Syn; Syn fl; Synov; Synovial fluid

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

Immune complex.IgG C1q binding assay Qn (Syn fld)Immune complex.IgG [Units/volume] in Synovial fluid by C1q binding assayIC IgG Snv C1Q Bind-aCncImmune complex.IgGSEROImmune Complex.IgG, Synovial fluidACnc

Frequently asked questions

Code details

Code42601-5

SystemLOINC

Display nameImmune complex.IgG C1q binding assay Qn (Syn fld)

DescriptionImmune complex.IgG

Short nameIC IgG Snv C1Q Bind-aCnc

ComponentImmune complex.IgG

PropertyACnc

TimingPt

System (specimen)Synv fld

ScaleQn

MethodC1q binding assay

ClassSERO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.16

Last changed2.69

Consumer names

Immune Complex.IgG, Synovial fluid

Part names

Immune complex.IgGACncPtSynv fldQnC1q binding assayArbitrary ConcentrationPoint in time (spot)Synovial fluid

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.