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Sunday, January 25, 2015
Arthritis and Rheumatism
What Does a Negative Rheumatioid Factor Indicate?
Can you tell me what it means when a blood test shows a rheumatoid factor of negative (<20iu/mi)?
A Rheumatoid Factor (RF) blood test is typically checked to help with the diagnosis of Rheumatoid Arthritis as anywhere between 70% to 85% of people with Rheumatoid Arthritis will have an elevation in their RF level. A 'negative' RF simply refers to the fact that the RF was within normal limits (in your case, less than 20 IUs per ml).
Raymond Hong, MD, MBA, FACR
Formerly, Assistant Professor of Medicine
School of Medicine
Case Western Reserve University