ɐn ˈɔːɹɡənˌɪzəm ɪz sˈuːɾəbəl fɚɹə dʒˌiːjˌuːˈɛs ɐsˈeɪ ɪf ɪt lˈæks nˈætʃɚɹəli əkˈɜːɹɪŋ bˈeɪɾəɡlˈuːkjʊɹɹˌɑːnɪdˌeɪs æktˈɪvᵻɾi ɔːɹ ɪf ðɪ æktˈɪvᵻɾi ɪz vˈɛɹi lˈoʊ bˈækɡɹaʊnd æktˈɪvᵻɾi.
An organism is suitable for a GUS assay if it lacks naturally occurring β-glucuronidase activity or if the activity is very low (background activity).