Rheumatoid factor

OtherAlso known as: RFAlso known as: Rheumatoid factor, serumAlso known as: IgM rheumatoid factor[IU]/mL

Detects rheumatoid factor antibodies that attack the body's own proteins.

Normal Range

14 [IU]/mL

[IU]/mL

Abnormal Levels

Consult your provider

Specimen Type

Blood

Why This Biomarker Matters

RF is a key indicator of autoimmune disease, particularly rheumatoid arthritis. Positive results suggest chronic inflammation and joint damage risk, warranting treatment to slow disease progression.

Understanding Your Results

Normal Range

14 [IU]/mL

Overview

Rheumatoid factor (RF) is an antibody that the immune system produces in some people. A positive RF test suggests the body is attacking its own tissues, which is characteristic of rheumatoid arthritis (RA) and other autoimmune conditions. However, RF can be positive without disease, and some RA patients test negative. RF is typically ordered along with other autoimmune markers like anti-CCP when evaluating joint pain or suspected autoimmune disease. Results help guide diagnosis and treatment decisions.

Technical Information (LOINC Codes)

Standardized laboratory codes for this biomarker

11572-5Primary

Rheumatoid factor [Units/volume] in Serum or Plasma

[IU]/mL

33910-1

Rheumatoid factor [Presence] in Serum

5297-7

Rheumatoid factor [Presence] in Serum by Latex agglutination

15205-8

Rheumatoid factor [Units/volume] in Serum by Nephelometry

[IU]/mL

15206-6

Rheumatoid factor [Units/volume] in Synovial fluid by Nephelometry

[IU]/mL

13634-1

Rheumatoid factor [Units/volume] in Synovial fluid

[IU]/mL

15204-1

Rheumatoid factor [Titer] in Serum by Nephelometry

{titer}

14034-3

Rheumatoid factor [Units/volume] in Cerebral spinal fluid

[IU]/mL

5300-9

Rheumatoid factor [Titer] in Serum by Sheep Cell Agglutination

{titer}

13930-3

Rheumatoid factor [Titer] in Synovial fluid by Agglutination

{titer}

6823-9

Rheumatoid factor [Presence] in Synovial fluid by Latex agglutination

15203-3

Rheumatoid factor [Units/volume] in Body fluid by Nephelometry

[IU]/mL

43932-3

Rheumatoid factor [Titer] in Body fluid

{titer}

30231-5

Rheumatoid factor [Units/volume] in Body fluid

[IU]/mL

6928-6

Rheumatoid factor [Units/volume] in Serum by Immunoassay

[IU]/mL

5299-3

Rheumatoid factor [Titer] in Serum by Latex agglutination

{titer}

17857-4

Rheumatoid factor [Titer] in Serum

{titer}

29351-4

Rheumatoid factor [Presence] in Cerebral spinal fluid

13929-5

Rheumatoid factor [Titer] in Synovial fluid by Sheep Cell Agglutination

{titer}

17534-9

Rheumatoid factor [Units/volume] in Body fluid by Immunoassay

[IU]/mL

25745-1

Rheumatoid factor [Presence] in Body fluid by Sheep Cell Agglutination

25746-9

Rheumatoid factor [Titer] in Body fluid by Sheep Cell Agglutination

{titer}

105081-4

Rheumatoid factor [Units/volume] in Specimen

[IU]/mL

31046-6

Rheumatoid factor [Presence] in Body fluid

45156-7

Rheumatoid factor [Presence] in Body fluid by Latex agglutination

5298-5

Rheumatoid factor [Presence] in Serum by Sheep Cell Agglutination

53562-5

Rheumatoid factor [Units/volume] in Pleural fluid

[IU]/mL

53924-7

Rheumatoid factor [Titer] in Synovial fluid by Latex agglutination

{titer}

63313-1

Rheumatoid factor [Units/volume] in Body fluid by Sheep Cell Agglutination

[IU]/mL

Available Lab Tests

Order tests that measure this biomarker

Rheumatoid Arthritis Basic Plus

$131.74

Rheumatoid Factor Test

$17.77

Results in 1-2 business days