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Rheumatoid Factor, Concentration — Catheter-Collected Specimen

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

Measures the concentration of rheumatoid factor in a catheter-collected specimen to help evaluate symptoms of rheumatoid arthritis and related autoimmune conditions.

Quick summary

["An elevated rheumatoid factor level can support an autoimmune evaluation, but it does not by itself confirm rheumatoid arthritis."]

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

Key facts at a glance

LOINC
37566-7
Short code
RF Views W contr via cath
Synonyms
RF Views W contr via cath
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 can attack the body's own tissues. This test measures the amount of RF in a specimen collected through a catheter. The exact type of specimen is determined by the test order and collection instructions.

Why might I need this test?

RF testing may be ordered when joint pain, swelling, morning stiffness, or other symptoms suggest rheumatoid arthritis or another autoimmune condition. It is usually interpreted with the examination, medical history, and other laboratory tests.

How is the test performed?

A clinician or trained collector obtains the sample through a catheter and sends it to the laboratory for analysis. The laboratory measures RF concentration using a validated testing method.

How do I prepare for the test?

Follow the collection instructions provided for the specific catheter procedure. Tell the healthcare team if you have an active infection, bleeding disorder, or recent catheter placement, because these factors may affect safe collection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Rheumatoid factor concentration

Frequently asked questions

What does a rheumatoid factor test measure?
It measures the concentration of rheumatoid factor, an antibody that can be associated with autoimmune joint disease.
Does an elevated result confirm rheumatoid arthritis?
No. RF can be elevated in other conditions and in some people without rheumatoid arthritis, so the result must be considered with symptoms, examination findings, and other tests.
Why is the specimen collected through a catheter?
A catheter allows the specimen to be collected directly from the intended body site. The specific fluid and preparation requirements depend on the procedure ordered.
  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