ARUP's Laboratory Test Directory

Rheumatoid Factors, IgA, IgG, and IgM by ELISA : 0051298

Mnemonic: RF PAN

Ordering Recommendation: May aid in prognostication for rheumatoid arthritis. Rheumatoid Arthritis Panel (2003277) is preferred for the workup of suspected rheumatoid arthritis or undifferentiated inflammatory arthritides.
Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Quantitative Enzyme-Linked Immunosorbent Assay.
Performed: Mon, Wed-Sat
Reported: 1-3 days
Specimen Required: Collect: Serum separator tube.

Specimen Preparation: Separate serum from cells ASAP or within 2 hours of collection. Transfer 0.5 mL serum to an ARUP Standard Transport Tube. (Min: 0.25 mL)

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Contaminated, hemolyzed, or lipemic specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
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): 83516 x2; 86431
Cross References: RF Isotypes (Rheumatoid Factors, IgA, IgG, and IgM by ELISA), RF3 (Rheumatoid Factors, IgA, IgG, and IgM by ELISA)