Sperm Analysis Retest Question

My DH had his first semen analysis 1.5 weeks ago. His results were not very good. 7.1 million out of the average 39 million. The doctor ordered a retest for him this week. I realize that sperm are constantly changing, but what will the second test prove? Is it possible to get a positive test if he indeed has low sperm count? If the second test is normal, does that mean the first was a fluke? Thanks for your help!!