Defining Variable Range In Sumif Function With VBA Within Table

I sum number of articles that are coming in on one sheet and articles going out on another. The total of In - Out is a separate value. All three values are placed on a third sheet.

The following code I use does the job, but I have to use a set range in the SumIf function. I want to be able to use a variable for the lastrow of a table colum.

VB:
Private Sub ArttotKnop_Click()

Dim Klanttel As Integer
Dim Rij, vLastRow, iLastRow As Long
Dim varResult, varMin, varTotal As Variant

iLastRow = Sheets("Ingebracht").ListObjects("Ingebracht").ListRows.Count
[Code] ....

Since my table grows larger every day I want to use variables.

Where I wrote A2:A500, B2:B500, B2:B550 and D2:D550 I want to be able to replace A500 and B500 with A and B + the variable iLastRow. The same for B550 and D550 with the vLastRow variable

Tried using:
.Range("A2:A" & iLastRow)
.Range("A2", Cells(iLastRow, 1))
.Range(Cells(2, 1), Cells(iLastRow, 1))

They don't work.