Question

What is a possible cause of the discrepancy that gives false positive when typing Rh (D-antigen) Blood? Type Rh pos but later discover it Rh neg

Answer 1

The reagents contains high protein polyclonal antibodies prepared from the human sera and containing high concentrations of protein were used for Rh typing. This may make false-positive reactions. when the test RBCs are coated with immunoglobulin. Spontaneous agglutination causing a false-positive results frequently.

False positive results form during experiments
1. Use of the wrong antiserum.
2. Warm autoagglutinins. Washing the cells multiple times and retesting or using IgM reagents
3. Reagent contaminated with a low-incidence antibody.
4. Polyagglutinable cells. These cells will be agglutinated by any reagent that contains human serum.