The Waaler Rose test is a slide hemaglutination method for the
qualitative and semi-quantitative detection of RF in human serum.
Stabilized sheep erythrocytes sensitized with rabbit IgG anti-sheep
erythrocyte are agglutinated when mixed with samples containing RF.
CLINICAL SIGNIFICANCE
Rheumatoid factors are a group of antibodies directed to determinants in
the Fc portion of the immunoglobulin G molecule. Although rheumatoid
factors are found in a number of rheumatoid disorders, such as systemic
lupus erythematosus (SLE) and Sjögren’s syndrome, as well as in
nonrheumatic conditions, its central role in clinic lays its utility as an aid
in the diagnosis of rheumatoid arthritis (RA).
An study of the “American College of Rheumatology” shows that the
80.4% of RA patients were RF positive.
PRECAUTIONS
Components from human origin have been tested and found to be negative for the
presence of HBsAg, HCV, and antibody to HIV (1/2). However handle cautiously as
potentially infectious.
CALIBRATION
The Waller Rose sensitivity is calibrated against the International RF
Reference WHO 64/1 Rheumatoid Arthritis Serum.
STORAGE AND STABILITY
All the kit components are ready to use, and will remain stable until the
expiration date printed on the label, when stored tightly closed at 2-8ºC
and contaminations are prevented during their use. Do not freeze: frozen
reagents could change the functionality of the test.
Always keep vials in vertical position. If the position is changed, gently
mix to dissolve aggregates that may be present.
Reagents deterioration: Presence of particles and turbidity.
ADDITIONAL EQUIPMENT
- Vortex mixer.
- Pippetes 50 µL
SAMPLES
Fresh serum. Stable 8 days at 2-8ºC or 3 months at –20ºC.
Samples with the presence of fibrin should be centrifuged before testing.
Do not use highly hemolized or lipemic samples.
PROCEDURE
Qualitative method
1. Allow the reagents and samples to reach room temperature. The
sensitivity of the test may be reduced at low temperatures.
2. Place 50 µL of the sample and one drop of each Positive and
Negative controls into separate circles on the slide test.
3. Mix the WR reagent vigorously or on a vortex mixer before using
and add one drop (50 µL) next to the samples to be tested.
4. Mix the drops with a stirrer, spreading them over the entire surface
of the circle. Use different stirrers for each sample.
5. Let the slide undisturbed on a flat surface for 2 minutes
6. After this time, twist very carefully the slide once to about 45º from
the horizontal and let the slide again to stay on a flat surface for 1
minute more.
Semi-quantitative method
1. Make serial two fold dilutions of the sample in 9 g/L saline solution.
2. Proceed for each dilution as in the qualitative method.
READING AND INTERPRETATION
Examine macroscopically the presence or absence of visible
agglutination immediately avoiding any movement or lifting the slide
during the observation. The presence of visible agglutination indicates
a RF concentration equal or greater than 8 IU/mL (Note 1).
The titer, in the semi-quantitative method, is defined as the highest
dilution showing a positive result.
