Test Name: RA Factor, Blood
Specimen Type: Serum
Specimen Required: 3-5 Cc Yellow Top Gel Vial
Day Performed: Daily
Reporting Time: 8 Hours STAT Reporting Time: 120 MINUTES Methodology: Beckman Coulter AU480
CLINICAL SIGNIFICANCE:
- Many people with rheumatoid arthritis or Sjögren syndrome have positive RA Factor tests. The higher the level, the more likely one of these conditions is present. Anti-cyclic citrullinated peptide antibody (anti-CCP antibody) is the additional test that can be done to help make the diagnosis as it is more specific for Rheumatoid Arthritis than RA Factor. A positive test for CCP antibody means Rheumatoid Arthritis is probably the correct diagnosis.
Higher levels of RA Factor may also be seen in the following conditions:
- Hepatitis C
- Systemic lupus erythematosus
- Dermatomyositis and polymyositis
- Sarcoidosis
- Mixed cryoglobulinemia
Mixed connective tissue disease
References:
- Aletaha D, Neogi T, Silman AJ, et al. 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Ann Rheum Dis. 2010;69(9):1580-1588. PMID: 20699241 pubmed.ncbi.nlm.nih.gov/20699241/.
- Darrah E, Rosen A, Andrade F. Autoantibodies in rheumatoid arthritis. In: Firestein GS, Budd RC, Gabriel SE, Koretzky GA, McInnes IB, O’Dell JR, eds. Firestein & Kelley’s Textbook of Rheumatology. 11th ed. Philadelphia, PA: Elsevier; 2021: chap 59.