CLINICAL SIGNIFICANCE
Brucella diagnostic may be assessed either by microorganism
isolation in blood or stools, or by titration of specific antibodies in the
patient serum. The reagent, because of its formulation in an acid
buffer, is reactive with both IgG and IgM antibodies and very useful for
the diagnosis of chronic individuals, which present a high level of IgG
antibody, difficult to be detected by the reference tube method
(Wright).
STORAGE AND STABILITY
All reagents are ready to use, and will remain stable until the expiration
date printed on the label, when stored tightly closed at 2-8ºC protected
from light and contaminations are prevented during their use. Do
not freeze: frozen reagents could change the functionality of the test.
Mix reagents gently before use.
Reagents deterioration: Presence of particles.
ADDITIONAL EQUIPMENT
- Mechanical rotator with adjustable speed at 80-100 r.p.m.
- Vortex mixer.
- Pippetes 50 µL.
SAMPLES
Fresh serum. Stable 7 days at 2-8ºC or 3 months at –20ºC.
Samples with presence of fibrin should be centrifuged before use.
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 R. Bengal reagent vigorously or on a vortex mixer before
using and add one drop next to the sample 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. Place the slide on a mechanical rotator at 80-100 r.p.m. for 4
minutes. False positive results could appear if the test is read
later than two minutes.
INTERFERENCES
Hemoglobin (10 g/L), lipemia (10 g/L) and rheumatoid factors (300
IU/mL), do not interfere. Bilirrubin interferes at 2.5 mg/dL. Other
substances may interfere5.
NOTES
Clinical diagnosis should not be made on findings of a single test
result, but should integrate both clinical and laboratory data.
