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Rheumatoid Factor (RF) Test

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

A blood test that measures rheumatoid factor, an antibody sometimes associated with rheumatoid arthritis and other inflammatory or autoimmune conditions.

Quick summary

["An elevated rheumatoid factor result may support an autoimmune diagnosis, but it must be interpreted with symptoms and other test findings."]

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

Key facts at a glance

LOINC
37182-3
Short code
RFA PA-L Views W contr IA
Synonyms
RFA PA-L Views W contr IA
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rf-angio
CPT
86430
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 this test?

Rheumatoid factor (RF) is an antibody that the immune system may produce in response to inflammation. This test measures the presence or amount of RF in a blood sample; the specimen and testing method may vary by laboratory.

Why might I need this test?

RF testing may be used to help evaluate joint pain, swelling, or stiffness, especially when rheumatoid arthritis is suspected. It may also be included with other antibody and laboratory tests when an autoimmune or inflammatory condition is being assessed.

How is the test performed?

A blood sample is collected and analyzed in the laboratory, often using an immunoassay, nephelometry, or another antibody-based method. The laboratory report will indicate whether the result is qualitative or quantitative.

How do I prepare for the test?

RF testing usually requires no special preparation or fasting. Follow any instructions provided by your healthcare professional or laboratory.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Rheumatoid factor

Frequently asked questions

Does a positive rheumatoid factor test mean I have rheumatoid arthritis?
No. RF can be present in other conditions and in some healthy people, so a positive result alone does not establish a diagnosis.
Is rheumatoid factor the same as anti-CCP testing?
No. RF and anti-CCP are different antibodies that are sometimes checked together. Anti-CCP is generally more specific for rheumatoid arthritis, while both results must be interpreted in clinical context.
Can my rheumatoid factor result change or become negative?
Yes. RF levels can vary over time, and they may decrease or become negative depending on the disease, its activity, and the individual. Your clinician may interpret repeat results alongside your symptoms and other findings.
  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