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Rheumatoid Factor, IgA by EIA (RDL)

CPT: 86431

Test Includes

This test is a component of Rheumatoid Factor Isotypes, IgG, IgA and IgM by EIA.

Expected Turnaround Time

7 - 14 days

Specimen Requirements




1 mL

Minimum Volume

0.3 mL (Note: This volume does not allow for repeat testing.)


Separate serum from cells within one hour. Transfer to a plastic transport tube before freezing.

Storage Instructions

Store frozen or refrigerated.

Stability Requirements



Room temperature

7 days


14 days


60 days

Freeze/thaw cycles

Stable x1

Causes for Rejection

Grossly hemolyzed; bacterial contamination; lipemic, icteric, non-serum specimen types

Test Details


EIA methods have the added advantage of being able to simultaneously detect RF of IgG and IgA subclasses in addition to RF IgM and are not susceptible to prozone. It has become apparent that the specificity and predictive value of the RF test is substantially increased by the detection of all three RF isotypes.


Enzyme-linked immunosorbent assay (ELISA)

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