Name: Rheumatoid Factor
Test Name: Rheumatoid Factor
Health Link Test Code: RF
LIS Test Code: RA
CPT Code(s): 86431
Days Performed: Daily, 24 hours.
In-Lab Turnaround Time: 4 hours.
Stat In-Lab Turnaround Time: 1 hour.
Collection Container: Red cap with yellow ring (SST)
Also Acceptable: Red top
Collection Volume: 3 mL
Pediatric Collection Volume: 1 mL
Sample Analyzed: Serum
Testing Volume: 1 mL
Pediatric Testing Volume: 0.3 mL
Centrifuge. Transfer cell-free serum to plastic vial.
Transport specimen to Laboratory. Transport with coolant pack if coming from clinic location; avoid freezing.
Ages 0 days and 15 years: 0-15 IU/mL
16 years and up: 0-29 IU/mL
Interpretation Type: Reference Interval
A negative result does not exclude rheumatoid arthritis. Approximately 25% of patients with a diagnosed case of rheumatoid arthritis may present with a negative result for RF.
Certain non-rheumatoid conditions, connective tissue disorders and a variety of other disease states such as hepatitis may elicit a positive RF test.
Autoimmune antibodies common with other systemic autoimmune diseases were not assessed.