ˈʌðɚ kəmpˈiːɾɪŋ sˈɪstəmz ɑːɹ bˈeɪst ˌɔn ˈiː.dʒˈiː. lˈuːsɪfɚɹˌeɪz, dʒˌiːˌɛfpˈiː, bˈeɪɾəɡˈælɐktˌɑːsɪdˌeɪs, klˈoːɹɐmfˌɛnɪkˌɑːl ˈæsɪtˌɪltɹɐnsfˌɜːɹeɪz sˌiːˌeɪtˈiː, ˈælkəlˌaɪn fˈɑːsfɐtˌeɪs.
Other competing systems are based on e.g. luciferase, GFP, beta-galactosidase, chloramphenicol acetyltransferase (CAT), alkaline phosphatase.