Rheumatoid Factor

Measures an autoantibody used in evaluating rheumatic diseases.

When rheumatoid arthritis is suspected, together with other clinical and laboratory findings.

1. Check in advance whether you need to fast or have your blood drawn at a specific time.
2. Not every biochemistry test needs special preparation. Check whether fasting is required for your specific order.
3. Before the blood draw, avoid unusually intense physical exercise unless your doctor has advised otherwise.
4. Tell your doctor and the laboratory staff about any medicines and dietary supplements you take.

Fasting is usually not required. If other tests have been ordered at the same time, follow the preparation they require.

A specific time is generally not required. If your doctor has set a different time, follow those instructions.

• Food, hydration or physical exercise, depending on the specific analyte
• Certain medicines or dietary supplements
• Hemolysis and delayed sample processing

Venous blood — serum or plasma, depending on the method

The blood sample is collected by a qualified staff member. The tube type, required volume, and processing and storage conditions are set by the laboratory's specific method. You do not need to store the sample yourself.

A positive RF is not a specific diagnosis of rheumatoid arthritis; it can also be found in other conditions.

If your result is outside the reference interval, you have symptoms, or your condition changes, contact your doctor. If symptoms are severe or develop quickly, seek emergency care.

Do not stop treatment on your own. Confirm the final test conditions with the laboratory.