Rheumatoid Factor
Label Mnemonic: RF
Epic code: LAB206
Order form: Laboratory Requisition
Supply order: Supply Order Form
Billing: Billing Policies
CPT code: 86431
Specimen(s):
Plasma
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL; whole blood in light green top tube or ONE Microtainer®.
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
<14 IU/mL
Test Limitations:
Criterion: Recovery within plus or minus 10% of initial value.

Icterus: No significant interference up to an I index of 60.

Hemolysis: No significant interference up to an H index of 300 
(approximate hemoglobin concentration: 300 mg/dL).

Lipemia (Intralipid): No significant interference up to an L index of 
2000.

There is poor correlation between turbidity and triglycerides 
concentration.

No high-dose hook effect up to RF activities of 6000 IU/mL.

Drugs: No interference was found at therapeutic concentrations using 
common drug panels.

Reference:
Glick MR, Ryder KW, Jackson SA. Graphical Comparisons of Interferences 
in Clinical Chemistry Instrumentation. Clin Chem 1986;32:470-474.
Methodology:
Immunoturbidimetric Assay
Sample Processing:
Centrifuge at a speed and time necessary to get barrier separation of plasma/serum and cells within 1 hour of collection. Send specimen in original tube. Do Not transfer to another tube.
Each sample must be labeled with at least TWO full patient identifiers (First/Last Name & DOB are sufficient for non-UIHC affiliated clients) to avoid sample rejection/delays.
Sample Storage:
Refrigerate.
All sample storage requirements are intended for delivery to UIHC within 24 hours of collection for testing. If samples won't arrive in this time period, please call the UIHC Core Lab for alternative storage/shipping instructions (319-356-3527).
Transport Instructions:
Place labeled specimen into zip-lock type biohazard bag; seal bag.
Place completed requisition into outside pocket of bag.
Transport in cooler with refrigerated coolant packs.
CPT Code:
86431