An improved method for the identification of butyrylcholinesterase phe
notypes is proposed. It is based on modifications of a method that use
s alpha-naphthyl acetate as substrate and DL-propranolol and Ro2-0683
as inhibitors. The proposed modifications make the method more rapid a
nd increase the accuracy of the determinations of the phenotypes teste
d (BCHE U, BCHE UF, BCHE UA, BCHE AK, BCHE AF, and BCHE A). These modi
fications make the method even more adequate for population studies an
d clinical routine.