Fish gelatin is commonly used in blocking solutions to minimise background noise in immunodetection procedures such as Western Blotting and immunostaining. Fish gelatin can be used to block non-specific binding sites on positively charged nylon or PVDF membranes or for blocking and dilution of antibodies during immunostaining procedures. Unlike BSA or milk, fish gelatin does not contain IgG or serum proteins that could cross-react with mammalian antibodies.