I did make ALT and AST experiment using ALT and AST human kits and read using spectrophotometer at wave length 530 first read and after 2 minutes i took the values to make the calculation but when I take the difference between 2 read most value 0 to -1 not make sense in this case i how i can do the calculation and the values were as control 400 inflammatory drug750 is this correct or must be less than this.