EN
FITC conjugate Bioveta, Ivanovice, Czech Republic, used in routine rabies diagnosis, gives a non-specific background fluorescence in brain impression slides. The effect may cause some problems in the proper diagnosis when only a small number of specific inclusion bodies are present. The paper presents an attempt to reduce the non-specific background fluorescence in preparations of brain impressions labelled with Bioveta antirabies conjugate adsorbed with the suspension of normal mouse brain or counterstained with Evans Blue. The background fluorescence has been markedly reduced and the increased number of inclusion bodies were also observed in impresions labelled by Bioveta conjugate with Evans Blue or adsorbed with normal mouse brain tissue in comparison to brain impressions labelled with Bioveta conjugate without these modifications. FA conjugate by diagnostics Pasteur was used as a reference because slides stained with this conjugate have not had any background fluorescence.