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Rheumatoid Factor (IgM) by Latex Immunoassay

Published: August 9, 2026Updated: August 16, 2026

This test measures the presence of rheumatoid factor, an antibody found in the blood that may indicate rheumatoid arthritis or other autoimmune conditions.

Quick summary

["Rheumatoid factor can help identify possible autoimmune diseases."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
82601-6
Short code
Latex (rHev b) 10 IgE Qn
Synonyms
Latex (rHev b) 10 IgE Qn
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is Rheumatoid Factor?

Rheumatoid factor is an antibody that targets the body’s own proteins, often found in people with rheumatoid arthritis. While it can be present in healthy individuals, higher levels may suggest an autoimmune response that requires further evaluation.

Why Might This Test Be Ordered?

Your healthcare provider may order this test to help diagnose or monitor rheumatoid arthritis, lupus, or other autoimmune diseases. It may also be used to assess disease activity or response to treatment.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is then analyzed using a latex-based immunoassay to detect rheumatoid factor antibodies in your serum.

What Are Common Results?

Results are typically reported as positive or negative. A positive result suggests the presence of rheumatoid factor, but it does not definitively diagnose rheumatoid arthritis alone. Additional tests and clinical evaluation are needed for diagnosis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgM Rheumatoid Factor

Frequently asked questions

Why was this test ordered?
This test may be part of a broader evaluation for autoimmune conditions, such as rheumatoid arthritis, where rheumatoid factor is a marker of potential inflammation or immune system dysfunction. It helps guide further testing or treatment planning.
What does a positive result mean?
A positive rheumatoid factor result indicates the presence of antibodies that target proteins in your blood. While this can be common in autoimmune diseases, it does not confirm a diagnosis alone. Your doctor will consider other factors, including symptoms, test results, and clinical findings.
Can this test be used to monitor treatment?
Yes, rheumatoid factor levels may be checked periodically to monitor disease activity or response to treatment, though they are not always the primary measure for this purpose. Other tests, such as inflammation markers, may be used alongside it.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy