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Test Code
RHEFR
Test Name
RF Isotypes IgG, IgA, IgM EIA
CPT Codes
86431 X 3
Included Tests
  • Rheumatoid Factor IgA
  • Rheumatoid Factor IgG
  • Rheumatoid Factor IgM
Expected Turnaround Time
14 - 21 days
Clinical Utility

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.
Specimen and Container Info

Specimen Type: Serum

Collection Container: Gold Top, Serum Separator

Alternate Collection Container: Red Top, Plain

Desired Specimen Volume: 4 mL
Collection Instructions
  1. Collect 2 gold top, serum separator tubes via venipuncture.
Processing and Submission Instructions
  1. Separate serum from cells within one hour of collection.
  2. Transfer 4 mL of serum to a clear aliquot tube (screw cap).
Transport Instructions

Transport to the laboratory refrigerated. 
Stability Requirements

Room Temperature

7 days

Refrigerated

14 days

Frozen

60 days

Freeze/Thaw Cycles

 Stable x1
Causes for Rejection
  • Grossly hemolyzed
  • Bacterial contamination
  • Lipemic specimen
  • Icteric specimen
  • Non-serum specimen types
Methodology
ELISA
Reference Intervals

See patient report.
Reference Lab
Labcorp Of America Holdings
Testing Schedule
Monday-Friday
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
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