Obstructive Sleep Apnea Tests Make an Appointment Refer a Patient Ask a Question Reviewed by Sheila Tsai, MD (March 01, 2017) Since people with OSA may complain of any number of sleep-related symptoms, including excessive daytime sleepiness, your doctor can order a range of tests to look for possible causes of those symptoms. Your doctor may order laboratory tests, including those to test for medications that are known to affect the level of alertness. The doctor also may check for thyroid disorders or other hormonal abnormalities. Your doctor may do a physical examination of your nose, mouth and throat, looking for large or extra tissues that might be blocking the flow of air. Your doctor may also ask you how well you sleep and how well you function during the day. Your doctor may want you to have an overnight sleep study, during which sensors record your physiologic data and your sleep. Sleep Study Your doctor may suspect that you have sleep apnea based on your symptoms, but an overnight sleep study is required to confirm the diagnosis. Learn more. Other Sleep Tests Multiple Sleep Latency Test (MSLT) This test, performed in a sleep laboratory, objectively determines your degree of sleepiness. On the day following an overnight sleep study, you will be asked to take four or five naps over an 8 – 10 hour period. Each nap period lasts about 20 minutes. During these nap periods, you will be closely monitored, as you were during your sleep study. Bring a book, crossword puzzles or anything else with which you can entertain yourself between naps. Maintenance of Wakefulness Test (MWT) This test measures your ability to stay awake. It consists of four nap opportunities, each lasting 40 minutes. During the nap period, you will be asked to try to stay awake. Most people without excessive sleepiness can remain awake during these nap periods. Nocturnal Oximetry Test Overnight Sleep Study for Children Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.