I took mine at ISU through Genex, not sure if there is one closer to you. There is a Genex rep in Ottumwa, Pat Larkin 641-777-0189. He might know if there is something close to you.
Doug Birt usually has a 2/3 day deal in Creston every spring. It should be a good one. Doug is the ABS rep for SW Iowa/NW, Mo. He has a Precott,Iowa Phone.