A New Superagglutination Test to Minimize False Negative and False Positive Results Common with Plate/Slide Agglutination Tests for the Diagnosis of Infectious Diseases.

ABSTRACT

Agglutination is the clumping of antigenic particles by antibodies. Several diagnostic kits for infectious diseases of animals and humans, based on slide agglutination/plate agglutination tests like the Rose Bengal Plate Test (RBPT) for diagnosis of brucellosis are used worldwide. False negative and false positive results are commonly encountered in these conventional agglutination tests. Simple, cost effective modifications can help in circumventing these problems. The novel Superagglutination Test reported here is a modified slide / plate agglutination test. False negative results due to smaller clumps formed by low titer of antibodies in serum are minimized by the addition of biotinylated antiglobulin followed by Avidin which forms easily detectable larger clumps. Similarly, prior staining of serum antibodies with a dye helps in differentiating a specific agglutinate formed by both antigen and antibody, from a non-specific aggregate of antigen alone that leads to false positive results. Superagglutination is more sensitive than the current agglutination tests and agglutination based diagnostic kits. The modification steps are easy to perform and give a more accurate diagnosis without much increase in the cost of the test. The economic losses to livestock industry caused by the spread of infectious diseases like brucellosis due to false negative diagnosis and culling/slaughtering of productive animals due to false positive diagnosis can be avoided by employing the new test.