Sub Macro1()
Dim oRng As Range, oNum As Range
    Set oRng = ActiveDocument.Range
    With oRng.Find
        Do While .Execute(findText:="[0-9]{1,}", MatchWildcards:=True)
            Set oNum = oRng.Words(1)
            If TestRegExp("[A-Z]", oNum.Text) = True Then
                oNum.HighlightColorIndex = wdYellow
            End If
            oRng.Collapse 0
        Loop
    End With
End Sub

Function TestRegExp(strFind As String, strText As String) As Boolean
Dim objRegExp As Object
Dim objMatch As Object
Dim colMatches As Object

    Set objRegExp = CreateObject("VBScript.RegExp")
    objRegExp.Pattern = strFind
    objRegExp.IgnoreCase = True
    objRegExp.Global = True
    If (objRegExp.Test(strText) = True) Then
        Set colMatches = objRegExp.Execute(strText)
        For Each objMatch In colMatches
            TestRegExp = True
            Exit For
        Next
    End If
    Set objRegExp = Nothing
    Set colMatches = Nothing
    Set objMatch = Nothing
End Function