Mine is done by Growmark..A division of Farm Service and Country Companies..
My oil supplier offers if for free..
The oil guy mentioned Black something is a good place to get it done..
Generally like stated above, if you do it a few times then you know what is going on and not much need for it down the road..
When I switched to another brand (Rotella)mentioned in this thread is showed on my next analysis in a negative way..Then I switched back and it straightened out the results..
I think most all oils are pretty dang good anymore, but the education of oil analysis is very interesting..