Rheumatoid Factor

General Information

Lab Name
Rheumatoid Factor
Lab Code
RF
Epic Name
Rheumatoid Factor
Synonyms
Latex, RF
Components

Interpretation

Guidelines
Method
Turbidimetric
Reference Ranges
(individual methods listed below)
Default Method
Units: IU/mL
Female Male Unknown
AgeRange AgeRange AgeRange
0-0-14 0-0-14 0-0-14

Effective date: 09/14/2026

UWMC Chemistry Remisol [UAUTO]
Units: IU/mL
Female Male Unknown
AgeRange AgeRange AgeRange
0-<15 0-<15 0-<15

Effective date: 08/31/2026

Ordering & Collection

Specimen Type
Blood
Collection

Preferred: 4 mL blood in GOLD SST or LIME GREEN PST tube
Also Acceptable: 4 mL blood in RED TOP, ORANGE TOP, GREEN TOP, or LAVENDER TOP tube

Handling Instructions

The laboratory must process the specimen within 2 hours of collection.

Quantity
Requested: 1 mL serum/plasma
Minimum: 0.5 mL serum/plasma

Processing

Receiving Instructions

Separate plasma/serum within 2 hours of collection and refrigerate. Avoid repeated freezing and thawing Stability: Room Temperature: up to 1 day; Refrigerated: 8 days; Frozen at -20°C: 3 months

Misc Sendout

Performance

Lab Department
Chemistry, Automated Panels(CHA)
Frequency
Daily
Available STAT?
No
Performing Location(s)
CL Renton Core Lab
206-520-4600

Clinical Lab, Room 170
1601 Lind Ave SW
Renton, WA 98057

UW-MT Chemistry, Automated
206-520-4600

Clinical Lab, Room NW220,
University of Washington Medical Center,
1959 NE Pacific street, Seattle, WA 98195

Billing & Coding

CPT Codes
86431
LOINC
11572-5
Interfaced Order Code
UOW2568
Interfaced Result Code
UOW2568