Test Code RHUF Rheumatoid Factor, LAB206
Methodology
Nephelometry
Performing Laboratory
St. Luke's Hospital Cedar Rapids
Specimen Requirements
Container/Tube:
Preferred: Green-top (lithium heparin) tube
Acceptable: Gold-top serum gel tube or plain
red top tube
Specimen Volume: 0.2 mL of plasma or
serum
Stability: Separate specimens within 2 hours of collection and analyze immediately
or store at 2 – 8 °C and analyzed within 7 days. For longer storage, samples
may be frozen at -20 °C for up to 3 months if frozen within 24 hours after collection.
Repeated freeze-thaw cycles should be avoided.
Reference Values
<15 IU/mL
Day(s) Test Set Up
Monday through Sunday
Test Classification and CPT Coding
86431
Useful For
The detection of RF is one of the criteria of the American Rheumatism Association (ARA) for the diagnosis of rheumatoid arthritis (RA), since 70 – 90% of patients with RA exhibit rheumatoid factors. Rheumatoid factors play an important role in the differential diagnosis between RA and other rheumatic diseases.
Analytic Time
STAT within 1 hour of receipt
Routine within 2 hours of receipt