Rheumatoid Factor (RF)

Rheumatoid Factor (RF) CPT: 86431

Expected Turnaround Time

Within 1 day

Specimen Requirements


Serum or plasma


1 mL

Minimum Volume

0.5 mL


Red-top tube, gel-barrier tube, lavender-top (EDTA) tube, or green-top (heparin) tube.


Not specified

Storage Instructions

Maintain specimen at room temperature.

Stability Requirements

Temperature Period
Room Temperature 14 days
Refrigerated 14 days
Frozen 14 days
Freeze/thaw/ cycles Stable x 3

Patient Information

To help diagnose the presence of an autoimmune disease such as rheumatoid arthritis (RA).

When you have joint pain and fatigue that your healthcare practitioner suspects may be due to RA.

A blood sample drawn from a vein in your arm.