Testing for sleep apnea can be a lucrative business, and labs have popped up in free-standing clinics and hospitals across the country. Over the past decade, the number of accredited sleep labs that test for the disorder has quadrupled, according to the American Academy of Sleep Medicine. At the same time, insurer spending on the procedure has skyrocketed. Medicare payments for sleep testing increased from $62 million in 2001 to $235 million in 2009, according to the Office of the Inspector General.