Abstract: A method, and associated kit, for assaying the activity of lysosomal enzymes present in dried bodily fluids and cell tissue samples, such as &agr;-L-iduronidase, &bgr;-D-galactosidase, &bgr;-D-glucosidase, chitotriosidase, total &agr;-D-galactosidase and &agr;-D-galactosidase A, hexosaminidase A and B, &agr;-D-mannosidase, &bgr;-D-mannosidase, &agr;-L-fucosidase, N-acetyl-&agr;-galactosaminidase, arylsulfatases, sphingomyelinase, &bgr;-galactocerebrosidase, iduronate-2-sulfatase and &bgr;-D-glucuronidase.