β-Casein is expressed as 13 genetic variants resulting from single nucleotide polymorphisms (SNP) in the CSN2 gene. The most frequent genetic variants in western dairy breeds are β-Casein A1 and β-Casein A2. The two types of β-Casein protein, A1 and A2, differ by a single-point mutation at amino acid position 82 (P82/H82). The Biosensis Bovine A2 β-Casein enzyme-linked immunosorbent assay (ELISA) Kit is a sandwich ELISA that allows the quantification of the bovine A2 β-Casein isoform in 5 hours. This kit consists of a pre-coated rabbit anti-bovine β-Casein polyclonal capture antibody, a chicken anti-bovine A2 β-Casein detection antibody and a horseradish peroxidase (HRP)-conjugated donkey anti-chicken IgY antibody. The addition of a substrate (3,3',5,5' -tetramethylbenzidine, TMB) yields a coloured reaction product which is directly proportional to the concentration of Bovine A2 β-Casein present in samples and protein standards. Extensive validation has shown accurate quantification of A2 β-Casein in full cream milk, skim milk and reconstituted A2 milk powder. Please refer to the kit protocol for specific use instructions. The A1 isoform is not detected in this ELISA assay.