Rheumatoid Factor Agglutination Test
A blood test that can help evaluate for rheumatoid arthritis and other conditions associated with inflammation or immune-system activity.
["A positive rheumatoid factor result supports an inflammatory or autoimmune condition but does not diagnose rheumatoid arthritis by itself."]
Key facts at a glance
- LOINC
- 26297-2
- Short code
- RFA Guided Vein-R CVC repos--W contr IV
- Synonyms
- RFA Guided Vein-R CVC repos--W contr IV
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- rf-angio
- CPT
- 85610
- SNOMED
- 396252006
- 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 can be found in the blood. This test may use an agglutination method, in which the laboratory checks whether RF causes antibodies and laboratory material to clump together.
Why might I need this test?
RF testing may be ordered when joint pain, swelling, or stiffness could be related to rheumatoid arthritis or another autoimmune condition. It may also be used alongside other laboratory and clinical findings.
How is the test performed?
A blood sample is collected and examined by the laboratory. For an agglutination assay, the sample is mixed with a reagent and observed for visible clumping, although the exact laboratory method can vary.
How do I prepare for the test?
RF testing usually requires no special preparation. Follow any instructions from your healthcare professional, and tell the laboratory if you have recently received certain treatments or taken medicines that could affect the result.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An elevated RF result may occur with rheumatoid arthritis, but it can also be found with other autoimmune conditions, some infections, and other illnesses. A negative result does not completely rule out rheumatoid arthritis, so results should be interpreted with symptoms, examination findings, and other tests.
Short name
Rheumatoid factor (RF) test
Frequently asked questions
Does a positive rheumatoid factor test mean I have rheumatoid arthritis?
Can someone with rheumatoid arthritis have a negative RF test?
Is this the same as an anti-CCP test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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