Abstract: A stable dry multi-layer analytical element for enzyme or triglyceride analysis in a fluid sample is prepared containing first and second layers on a support. The first layer contains a tetrazolium salt as a dye forming precursor. The second layer is adjacent the first layer and contains an electron-transmitting agent. Either layer contains a co-enzyme in oxidized form and either layer contains a reagent containing an enzyme substrate, enzyme or co-enzyme other than the oxidized co-enzyme. The analytical element has improved storage stability and low fog density before and after storage.