LOINCActiveBoth

LOINC Code 33577-8: Rheumatoid factor IgM Nephelometry (S) [Titer]

33577-8 is a LOINC code used to identify Rheumatoid factor IgM Nephelometry (S) [Titer] 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 Rheumatoid factor.IgM. 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 Rheumatoid factor.IgM. 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: ACTIVE
  • Order vs observation: Both
  • Method: Nephelometry

What it does not mean

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

Key facts

  • Rheumatoid factor IgM [Titer] in Serum by Nephelometry
  • Rheumatoid factor.IgM
  • Dilution factor; Dilution Factor (Titer); Fac; Fact; Immune globulin M; Immunoglobulin M; Light scattering; Nephelom; Point in time; Random; RF; RF IgM; Serology; Serum; SmQn; SR; Titer; Titered; Titre; Ttr

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

Rheumatoid factor IgM Nephelometry (S) [Titer]Rheumatoid factor IgM [Titer] in Serum by NephelometryRF IgM Titr Ser NephRheumatoid factor.IgMSERORheumatoid factor IgM, BloodTitr

Frequently asked questions

Code details

Code33577-8
SystemLOINC
Display nameRheumatoid factor IgM Nephelometry (S) [Titer]
DescriptionRheumatoid factor.IgM
Short nameRF IgM Titr Ser Neph
ComponentRheumatoid factor.IgM
PropertyTitr
TimingPt
System (specimen)Ser
ScaleSemiQn
MethodNephelometry
ClassSERO
Example unitstiter
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.09
Last changed2.75

Consumer names

Rheumatoid factor IgM, Blood

Part names

Rheumatoid factor.IgMTitrPtSerSemiQnNephelometryRheumatoid factor IgMTiterPoint 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 33577-8 | HealthAssure