VBA Macro triggering too often - vba

Question

My worksheet is set up with data validation dropdowns and I am wanting a macro to ONLY trigger when the value of the cell is changed from another value in the dropdown, not from the default "empty" value.
Here is what I am trying to use:
Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Column = 5 Then
If IsEmpty(Target.Value) = True Then
MsgBox "Test1"
Else
MsgBox "Test2"
End If
End If
exitHandler:
Application.EnableEvents = True
Exit Sub
End Sub
My problem is that this "IsEmpty" command is reading the cell AFTER the selection not before. I want it to read what the cells value was BEFORE the selection not after.
How can I do this?

Answer 1

Example approach:
Const COL_CHECK As Long = 5
Private oldVal
Private Sub Worksheet_Change(ByVal Target As Range)
Dim c As Range
Set c = Target.Cells(1) '<< in case multiple cells are changed...
If c.Column = COL_CHECK Then
If oldVal <> "" Then
Debug.Print "changed from non-blank"
Else
Debug.Print "changed from blank"
End If
End If
exitHandler:
Application.EnableEvents = True
Exit Sub
End Sub
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim c As Range
Set c = Target.Cells(1)
oldVal = IIf(c.Column = COL_CHECK, c.Value, "")
Debug.Print "oldVal=" & oldVal
End Sub

Answer 2

Another approach:
This will need one cell per validation-dropdown:
Function ValChange(Cell2Follow As Range) As String
ValChange = ""
If Len(Application.Caller.Text) = 0 Then Exit Function
If Application.Caller.Text = Cell2Follow.Text Then Exit Function
MsgBox "value of the cell is changed from another value in the dropdown" & vbLf & "not from the default 'empty' value"
End Function
in a different cell, assumed the dropdown is in E6:
=E6&ValChange(E6)
application.caller.text will be the old value
(calculation must be automatic)