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HelpTest Code RF Rheumatoid Factor
Additional Codes
Epic: LAB206
Specimen Required
Specimen Type: Serum
Collection Container/Type
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 3 mL
Collection Instructions: Centrifuge and separate cells after clot formation and within 4 hours of collection.
Specimen Minimum Volume
0.25 mL
Specimen Stability
Room temperature: 24 hours
Refrigerated: 3 days
Frozen: 1 month
Clinical Significance
Rheumatoid factor (RF) is an autoantibody against human immunoglobulin G (IgG) commonly present at a high concentration in sera of patients with certain conditions, particularly in patients with rheumatoid arthritis.
The measurement of rheumatoid factor is useful in evaluating the diagnosis, effects of therapy, and prognosis of diseases such as rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, cryoglobulinemia, and chronic hepatopathy. This assay is designed to accurately and reproducibly measure serum rheumatoid factor using agglutination.
Reference Range
<30 IU/mL
Rejection Due To
Unlabeled, mislabeled, wrong tube type, hemolyzed, visually lipemic, QNS, exceeds specimen/stability requirements.
Day(s) and Time(s) Performed
Daily
Report Available
Same day
Method Name
Immunoturbidimetric
LOINC
11572-5
Limitations
nterferon Alfa-2a and methotrexate may decrease serum rheumatoid factor concentration.
Methyldopa, oral contraceptives, and oxyphenisatin may increase serum rheumatoid factor levels.
Nonsteroidal anti-inflammatory drugs may decrease or have no significant effect on serum rheumatoid factor levels.