Apr 18, 2017




Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Chemistry

Rheumatoid Factor

Rheumatoid Factor (RF) Chemistry Lab Test

Name: Rheumatoid Factor

Test Name: Rheumatoid Factor

Health Link Test Code: RF

LIS Test Code: RA

CPT Code(s): 86431

Methodology: Immunoturbidimetry

Days Performed: Daily, 24 hours.

In-Lab Turnaround Time: 4 hours.

Stat In-Lab Turnaround Time: 1 hour.

Specimen: Blood

Collection Container: Red cap with yellow ring (SST)

Also Acceptable: Red top

Collection Volume: 3 mL

Pediatric Collection Volume: 1 mL

Stability Ambient:

1 day

Stability Refridgerated:

3 days

Stability Frozen:

1 month

Sample Analyzed: Serum

Testing Volume: 1 mL

Pediatric Testing Volume: 0.3 mL

Specimen Processing:

Centrifuge. Transfer cell-free serum to plastic vial.

Specimen Transport:

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

Additional Information:

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.