Rheumatoid Factor (IgM)

For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

Test Code

CPT Codes

Preferred Specimen
1 mL serum collected in a red-top tube (no gel)

Patient Preparation
Overnight fasting is preferred

Minimum Volume
0.3 mL

Transport Temperature
Refrigerated (cold packs)

Specimen Stability
Room temperature: 48 hours
Refrigerated: 8 days
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Gross lipemia • Grossly icteric • Heat treated samples • Serum separator tube (SST®)

Immunoassay (IA)

Setup Schedule
Set up: Tues, Sat; Report available: 1-4 days

Reference Range
≤6 Negative
>6 Positive

Clinical Significance
In conjunction with clinical findings and other laboratory tests, the presence of rheumatoid factor (RF) can be used to aid in the diagnosis of rheumatoid arthritis.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

Last Updated: December 6, 2021

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.