Rheumatoid Factor (RF) Assay Kit – Bulk Reagents


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Selling unit: per 100ml

Product Name

  1. Common name: Rheumatoid factor (RF) assay kit (latex-enhanced immunoturbidimetric method)
  2. English name: RF Reagent Kit (Immunoturbidimetric Method)

Reagent Ratio

3:1, 4:1, 5:1, common ratio 4:1, other ratios need to be customized

Intended Use

This reagent is used to determine the amount of RF in human serum.

RF is a specific antibody against the antigenic determinant cluster on the Fc fragment of the human IgG molecule and is an anti-IgG autoantibody whose high concentration in the serum is commonly seen in rheumatoid arthritis. The rheumatoid factor test is useful in the diagnosis of rheumatic diseases, systemic lupus erythematosus, and chronic hepatitis, and as an indicator of disease progression.

Test Principle

The RF in the sample reacts with the denatured human IgG antibody hypersensitized by latex particles and an agglutination reaction occurs, and the change in absorbance is detected at a wavelength of 570-610 nm, and the degree of change is proportional to the RF content in the sample.

Main Components

Reagent components included in the product.

Rheumatoid Factor (RF) Assay Kit & Bulk Reagents

*Components are not interchangeable in kits with different lot numbers.

*Reagent components not included in the product, but necessary for the test: outsourced normal and abnormal QCs and calibrators.

Storage Conditions And Expiration Date

The kit is stored at 2-8°C away from light and is valid for one year.

Reagents that have been opened are careful not to be contaminated, and reagents are stable in the instrument compartment (2-8°C) for one month.

The reagents must not be frozen.

Applicable Instruments

Hitachi 7180/7600; Olympus AU680/2700; Toshiba TBA120; Myriad BS2000M/480; Siemens ADVIA 1800/2400 series automatic biochemical analyzers.

Sample Request

Fresh serum, which should be separated within 2 hours after blood collection, can be stored at room temperature (15-25°C) for 24 hours, 2-8°C for 3 days, and -20°C for 4 weeks.

Test Method

  1. Reagent preparation: liquid reagents are ready to use out of the bottle.
  2. test conditions: (different parameters on the machine can be requested according to different testing instruments)

Rheumatoid Factor (RF) Assay Kit & Bulk Reagents

Operation steps.

Rheumatoid Factor (RF) Assay Kit & Bulk Reagents

Reagents and sample volumes can be increased or decreased in proportion to the requirements of different biochemical analyzers.

  1. Calibration procedure.

Landau calibrators are recommended.

  1. QC control procedures.

It is recommended that each laboratory establish its own quality control system and select appropriate quality control products for quality control. The measured values of QC products should be within the specified range. If outside the specified range, it is necessary to take appropriate measures or contact the manufacturer.

  1. Calculation.

5 points are calibrated and the corresponding values are entered. The standard curve is plotted with △A as the vertical coordinate and the concentration as the horizontal coordinate, and the standard curve is corrected with a suitable mathematical model such as Spline model, and this standard curve is saved and used to calculate the results.

Positive Judgment Value Or Reference Interval

0~20 IU/mL

It is recommended that each laboratory establish its own reference range of normal values.

Interpretation Of Test Results

Bilirubin ≤ 40 mg/dL, hemoglobin ≤ 500 mg/dL and celiac ≤ 500 mg/dL did not interfere with the determination.

Limitations Of The Test Method

The measurement of RF in human serum is only one of the indicators used by clinicians to diagnose patients, and clinicians must also make a comprehensive judgment based on the patient’s physical symptoms, medical history, and other diagnostic items and diagnostic tools.

Product Performance Index

Absorbance of reagent blank: wavelength 604 nm, optical diameter 1.0 cm, temperature 37°C, A0  ≤ 1.0.

Analytical sensitivity: the absorbance change value ΔA≥0.05 when the kit tests 30 IU/ml of the assay.

Linearity range: test serum samples, reagent linearity in the interval of 6~120 IU/ml, linear correlation coefficient|r| should not be less than 0.975; in the interval of 6~20 IU/ml, the absolute deviation of linearity should not exceed 2IU/ml; in the interval of (20~120 IU/ml, the relative deviation of linearity should not exceed ±10%.

Precision: repeatability CV≤ 8.0%; relative extreme difference between batches≤ 10.0%.

Accuracy: Relative deviation ≤ 10%.


  1. This product is for in vitro diagnosis only.
  2. Avoid contamination when using the reagent, the container used must be clean, and please take necessary precautions, do not swallow, and avoid contact with skin and mucous membrane.
  3. Please dispose of the measured samples and waste liquids in accordance with the relevant national and local laws and regulations.
  4. Please dispose of the measured samples and waste liquids according to the relevant national and local laws and regulations.
  5. When changing the reagent lot number, the calibration should be re-calibrated.
  6. The latex reagent (R2) itself has a certain turbidity, and its particle diameter is 100 nm-200 nm, the trace has strong Brownian motion in the solution, so the reagent does not need to be shaken well before use.


  1. Koopman, W.J. and Schrohenloher, R.E., “Rheumatoid factor and human disease,” Clinical Immunology Newsletter (1990); 10, 137-41.
  2. Center for Disease Control, “Reference preparation of rheumatoid factor.” Catalog #ISO949, Atlanta, GA, Lot 87-0094.
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