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Rheumatoid Factor (RF), Venous Blood

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

A blood test that detects or measures rheumatoid factor, an antibody sometimes associated with inflammatory joint diseases.

Quick summary

["A positive or elevated RF result may support a diagnosis of rheumatoid arthritis but is not diagnostic by itself."]

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

Key facts at a glance

LOINC
24626-4
Short code
RFA Guided Vein CVC repos--W contr IV
Synonyms
RFA Guided Vein CVC repos--W contr IV
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?

This test examines a venous blood sample for rheumatoid factor (RF), an antibody that can target a patient's own immunoglobulin G. The exact assay method is not clear from the abbreviated code.

Why might I need this test?

RF testing may be ordered when joint pain, swelling, stiffness, or other symptoms suggest an autoimmune or inflammatory condition. It can also be used alongside other laboratory and clinical findings when evaluating possible rheumatoid arthritis.

How is the test performed?

A healthcare professional draws blood from a vein, and a laboratory analyzes the sample for RF. The result may be reported as present or absent, or as a measured concentration, depending on the laboratory method.

How do I prepare for the test?

RF testing usually requires no fasting or special preparation. Follow any instructions from your healthcare professional, particularly if the test is being ordered at the same time as other blood tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A positive or elevated RF result can occur in rheumatoid arthritis, but it may also be present with other autoimmune diseases, some chronic infections, and certain other conditions. RF must be interpreted with symptoms, examination findings, and other tests because it does not establish a diagnosis by itself. A negative result does not completely exclude rheumatoid arthritis.

Short name

Rheumatoid factor (RF)

Frequently asked questions

Does a positive rheumatoid factor mean I have rheumatoid arthritis?
No. A positive result can support the diagnosis, but it may also occur in other conditions or in healthy people, so your clinician will interpret it with your overall health findings.
Can I have rheumatoid arthritis with a negative RF result?
Yes. Some people with rheumatoid arthritis have a negative or only mildly elevated RF result, so other clinical and laboratory findings are also important.
Do I need to fast before this test?
Fasting is generally not required for RF testing. Follow the specific preparation instructions provided for your blood draw, especially if additional tests are being performed.
  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