Sub Test()

   Rows.Hidden = False
   DoIt 44

End Sub

Private Sub DoIt(DColor)
Dim rngC As Range, c As Range, x As Long

   Set rngC = Range(Cells(6 + 1, 21), Cells(Rows.Count, 21).End(xlUp))
   For x = rngC.Cells.Count To 1 Step -1
      If rngC.Cells(x).DisplayFormat.Interior.ColorIndex = DColor Then _
      rngC.Cells(x).EntireRow.Hidden = True
   Next x

End Sub