If you mean you want to click item(5) no matter what it is, then use the object name to click it instead of the text.
If that's not quite it, yes, please post pictures. 🙂
ListView20WndClass ClickItem "M_Conc5_HC", ...
Clicks the 0 subitem of the 'M_Conc5_HC' item of the 'ListView20WndClass' list view.
This is how you look at the Name Mapping
ClickItem as a method can take either a string or an integer. So, if you ALWAYS want to click on the 5th item in the list, you simply do ClickItem(5). If you always want to click on the same text in the list, regardless of position, you do ClickItem(<item text>).
Since you're using Keyword test, it's simply a matter of editing the operation after the recording and going to the parameter and changing the type from "string" to "integer" and entering in the desired value.