Is One or Two Day Testing Better?
Most labs still conduct one-day testing, but evidence suggests that one-day testing can’t accurately determine the severity of your sleep apnea. That could be a real problem if you were diagnosed too lightly! One night testing could miss mild to moderate obstructive sleep apnea up to 60% and 84% of the time, as found by researchers in two studies. A third study found that the severity of obstructive sleep apnea was misdiagnosed in one-night testing.
Each potential sleep apnea patient is measured on a scale called the average apnea-hypopnea index (AHI). Patients are given a number based on the number of apnea events (stoppage in breathing) plus the number of hypopneas (shallow breathing) that occur on average each hour. Each episode or event must last at least 10 seconds to qualify.
Less than 5 = no sleep apnea
5 – 15 = mild sleep apnea
15 – 30 = moderate sleep apnea
Over 30 = severe sleep apnea
47,423 adults were assessed in a published study in the Journal of Clinical Sleep Medicine. On average, AHI was 26.9, with an average variance per night of 5.5. More than one-third of the people in the study had a significant variance that would put them into a new severity category.
Adding another night of testing will reduce the amount of inaccurate sleep apnea diagnoses.