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Rheumatoid Factor (RF) Test

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

A blood test that measures rheumatoid factor antibodies, which are sometimes associated with rheumatoid arthritis and other conditions.

Quick summary

["An elevated rheumatoid factor result can support a possible autoimmune diagnosis but must be interpreted with symptoms and other tests."]

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

Key facts at a glance

LOINC
43478-7
Short code
RF Guided BD+PD Endo--1.5h p con ret IB
Synonyms
RF Guided BD+PD Endo--1.5h p con ret IB
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, or RF, is an antibody that can be increased in rheumatoid arthritis and some other autoimmune or chronic infections. The test measures the amount of RF in a blood sample.

Why might I need this test?

Your clinician may order this test when joint pain, swelling, or stiffness could be caused by rheumatoid arthritis or another autoimmune condition. It may also be used to help assess the course of an existing rheumatologic condition.

How is the test performed?

A blood sample is collected and analyzed in the laboratory to determine the amount of rheumatoid factor present. The laboratory method may vary, so the test report should be reviewed with your clinician.

How do I prepare for the test?

This test usually requires no special preparation. Follow any instructions provided by your healthcare professional, particularly if other laboratory tests are being performed at the same time.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Rheumatoid factor

Frequently asked questions

Does an elevated rheumatoid factor mean I have rheumatoid arthritis?
No. A high result can increase suspicion for rheumatoid arthritis, but symptoms, physical examination, and other tests such as anti-CCP antibodies are also needed to make a diagnosis.
Can someone with rheumatoid arthritis have a normal result?
Yes. Some people with rheumatoid arthritis have little or no detectable rheumatoid factor, so a normal result does not completely rule out the condition.
What other conditions can cause an elevated result?
Other autoimmune conditions and certain chronic infections can raise rheumatoid factor levels. The result should be interpreted in the context of your overall health and clinical 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