IUI - what does his sperm need to be at

So, we were told beginning of February my husband had an extremely low sperm count and we weren't candidates for an IUI. After more tests, all his levels came back normal and he had no varicoceles. So, they have no explanation. The urologist suggested we do a second semen analysis, which we did Thursday and find out the results Monday. Does anyone know what his count needs to be for us to be considered for an IUI?!