Reference Interval:
| Test Number
| Components
| Reference Interval
| | | Rheumatoid Factor, IgG by ELISA
| 20 U/mL or less
| | | Rheumatoid Factor, IgM by ELISA
| 25 IU/mL or less
| | | Rheumatoid Factor, IgA by ELISA
| 35 U/mL or less
|
|
| Interpretive Data: |
The presence of abnormal levels of all three rheumatoid factor (RF) isotypes has a specificity of 99 percent for RA. However, RF in any isotype combination may be found in hepatitis C, Sjogren syndrome, and other chronic infections.
|
| CPT Code(s): |
86430 x2 RF IgA/IgG; 86431 RF IgM
|
Cross References: |
RF Isotypes (Rheumatoid Factors, IgA, IgG, and IgM by ELISA), RF3 (Rheumatoid Factors, IgA, IgG, and IgM by ELISA) |