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HelpTest Code RHUT Rheumatoid Factor, Serum
Reporting Name
Rheumatoid Factor, SUseful For
Diagnosis and prognosis of rheumatoid arthritis
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumAdditional Testing Requirements
An alternative or complementary assay to rheumatoid factor (RF) that has demonstrated utility in the diagnosis and assessment of rheumatoid arthritis (RA) is CCP / Cyclic Citrullinated Peptide Antibodies, IgG, Serum. Utilization of both tests can provide clinical value in the diagnosis of RA. RF is not specific and may be present in other inflammatory rheumatic diseases and nonrheumatic diseases as well as in nonaffected individuals, especially in those 60 years of age or older.
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL serum
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
Serum: 0.75 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 14 days |
| Ambient | 14 days | |
| Frozen | 14 days |
Reference Values
<15 IU/mL
Day(s) Performed
Monday through Friday
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
86431
Clinical Information
Rheumatoid factors (RF) are a heterogeneous group of autoantibodies associated with the diagnosis of rheumatoid arthritis (RA) and can also be found in other inflammatory rheumatic and nonrheumatic conditions as well as in some healthy individuals aged 60 years and older. Despite being nonspecific, the detection of RF or anti-citrullinated protein (anti-CCP) antibody is part of the 2010 diagnosis criterion of the American College of Rheumatology for classification of RA. More than 75% of patients with RA have an IgM antibody to IgG. The titer of RF correlates poorly with disease activity, but those patients with high titers tend to have more severe disease and, thus, a poorer prognosis than seronegative patients.
A meta-analysis compared the sensitivity and specificity of IgM RF versus anti-CCP antibody. For IgM RF, the sensitivity was 69% (CI, 65%-73%) and specificity was 85% (CI, 82%-88%). For comparison, the sensitivity for anti-CCP antibody was 67% (95% CI, 62%-72%) and 95% (CI, 94%-97%).(1) Both anti-CCP and RF are useful in the diagnosis of RA, and the use of both tests has been shown to increase diagnostic sensitivity.(2)
Report Available
1 to 3 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Method Name
Turbidimetry
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Kidney Transplant Test Request
-Renal Diagnostics Test Request (T830)