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Rheumatoid Factor (RF) Test

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

A blood test that detects rheumatoid factor antibodies, which may help evaluate suspected rheumatoid arthritis and related autoimmune conditions.

Quick summary

["A positive rheumatoid factor result can support a rheumatology evaluation but is not diagnostic by itself."]

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

Key facts at a glance

LOINC
44213-7
Short code
RF Guided PD Endo--W contr Retro
Synonyms
RF Guided PD Endo--W contr Retro
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
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 some people with rheumatoid arthritis produce. The test measures or detects RF in a blood sample and may be used with other findings to assess whether an autoimmune condition is likely.

Why might I need this test?

Your clinician may order an RF test if you have joint pain, swelling, morning stiffness, or symptoms suggesting rheumatoid arthritis. It may also be used to help evaluate other autoimmune or inflammatory conditions.

How is the test performed?

A blood sample is collected and analyzed in the laboratory. Some laboratories report RF as present or absent, while others provide a concentration or titer; the exact method is not clear from the test code.

How do I prepare for the test?

This test usually requires no special preparation. Tell your clinician about autoimmune diseases, recent infections, pregnancy, and medicines you are taking, and do not stop prescribed medication unless instructed.

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 result mean I have rheumatoid arthritis?
No. RF can support a diagnosis when combined with compatible symptoms and other testing, but it is not specific enough to diagnose rheumatoid arthritis by itself.
Can someone with rheumatoid arthritis have a negative RF result?
Yes. Some people with rheumatoid arthritis have little or no detectable RF, so a negative result does not rule out the condition when symptoms strongly suggest it.
What other tests may be used with rheumatoid factor?
Your clinician may also order anti-CCP antibodies, inflammatory markers, and tests that assess inflammation or joint involvement. These results are interpreted together rather than in isolation.
  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