Workday Function to add Workdays

I'm trying to run code based off of dates in the D column. The code below works. But the "if" part of the conditional formatting needs to be + 30 workdays, not plus thirty days. I'm assuming that the WORKDAY function helps with this. But when I try + workday(30) and things like that, I don't get anywhere.

For Each oKey In oDictionary.keys
    Editing_Sheet.Range("A1").CurrentRegion.AutoFilter Field:=1,    Criteria1:=CStr(oKey)
    LastRowFiltered = Editing_Sheet.Cells(Rows.Count, "A").End(xlUp).Row
        If Range("D" & LastRowFiltered) <= Date + 30 Then
         'run code'