Rheumatoid factor FS

Product Number: 1 7022


Rheumatoid factors (RF) are a group of autoantibodies belonging to all immunoglobulin classes directed against the Fc fragment of altered or complex IgG. Diagnostic tests for RF determination identify mainly RF of the IgM class, which are detectable in several rheumatic diseases, mainly of inflammatory origin. RF occurs in approx. 70 – 80% of patients with rheumatoid arthritis (RA), but they are not specific for RA as elevated concentrations are also observed in various non-rheumatic diseases and in approx. 10% of the elderly population without clinical symptoms of RA. The presence or absence of rheumatoid factors represents a valuable tool in the differential diagnosis of rheumatic diseases. Additionally, high RF concentrations in RA are often associated with a more progressive clinical course of the disease. However, a positive RF value has to be confirmed by clinical and other laboratory findings. [1-4]


Ready to use reagent.

Proline Rheumatoid factor FS comes in a liquid format which provides convenience for users as no reconstitution is required which helps reduce the risk of misdiagnosis.

Open system reagent, compatible with a wide range of instruments.

Proline Rheumatoid factors FS reagent is suitable for various third-party analyzers such as Abbott, Advia, Cobas, Hitachi, Olympus, Response, TokyoBoeki, and Beckman Coulter. Please contact our technical support at for further compatibility information on other types of analyzers.


  • Immunoturbidimetric test (Particle enhanced)
  • No effect of prozone was observed up to 3000 IU/mL.
  • No interference: ascorbic acid 30 mg/dL, bilirubin 60 mg/dL, hemoglobin 300 mg/dL, lipemia to triglycerides 1200 mg/dL
  • Measurement ranges from 10-500 IU/mL with a lower limit of detection of 2 IU/mL


  • TruCal RF


Kit Lines

No. Catalog R1 R2 Kit Size
1 7022 99 88 021 5 x 25 mL 1 X 25 mL Multi Purpose Kit
1 7022 99 88 921 4 X 18 mL 4 X 4 mL Proline® R-910

Reference Range

Rheumatoid factor FS is an immunoturbidimetric test to determine rheumatoid factors (RF) in serum and heparin plasma. Increased RF levels can aid in the diagnosis of patients with suspected rheumatic arthritis. High RF concentrations are often associated with a more progressive clinical course of disease.

Healthy Population < 15 IU/mL (95th percentile)
Cut-off < 19 IU/mL

Each laboratory should check whether the reference range can be calculated for its patient population and determine its own reference range if necessary.


  • Inflamation

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