Extraer dato de nodo xml

Dim respuesta As String = "<TRACKID>1234568</TRACKID>"

Dim nodo As String = "<TRACKID>"
Dim nodoCount As String = nodo.Lenght


Dim i As Integer = respuesta.IndexOf("<TRACKID>") + 9
Dim j As Integer = respuesta.IndexOf("</TRACKID>")

Dim dato As String = respuesta.Substring(i , j - i)