Veterinary Epidemiology and Zoonosis

Rapid Plate Agglutination Test

DIAGNOSIS OF BRUCELLOSIS BY RAPID PLATE AGGLUTINATION TEST

• The test is mainly used for screening of brucellosis in a herd to detect the presence of infection qualitatively.
• It is a rapid test, useful in screening large number of sera samples quickly.

Materials required

Materials required	Quantity and purpose
Brucella abortus coloured antigen (available at IVPM, Ranipet)	30µL per sample
Known brucella positive and negative serum	Each 30µL per test
Clean glass slide or White tile	One
Test serum suspected for brucellosis	30µL per test
Micropipette and microtips	Adequate numbers

Procedure

• Take a clean slide or a white tile, and add a drop of suspected serum (~30µL) at one corner and a drop of positive serum (~30µL) at the other corner.
• Place a drop of Brucella abortus coloured antigen to the serum drops.
• Mix thoroughly with a glass rod and allow the reaction to take place.
• Observe for agglutination.
• Always keep positive and negative controls.

Interpretation of result

• Positive for brucellosis: Agglutination occurs in 5-8 minutes, which varies in intensity depending on the concentration of antibodies.
• Negative for brucellosis: No visible agglutinated clumps.

Note

• All positive samples should be retested by a confirmatory test.
• False-negative reactions may occur and can be detected by retesting animals at intervals over a period of at least 3 months.