Patch testing with serial dilutions of various isothiazolinones in patients hypersensitive to methylchloroisothiazolinone/methylisothiazolinone

In 2005, methylisothiazolinone (MI) on its own came into use as a preservative. Prior to that, MI was always present together with methylchloroisothiazolinone (MCI). Can the pattern of reactivity to the separate active ingredients in allergic patients tell us something about the primary sensitizer?