Why standard home test said AHI 8 (twice) but WatchPAT said AHI 46

[Fabrice01]

Hospital's respiratory department had me do the same standard home test once in 2017 and again in 2022. There's a little thingy going in the nostrils (presumably to check breathing), an electrode to be taped on the chest and a finger probe. All of this to be worn the whole night once. In 2017 it yielded AHI = 8, and in 2022 almost the same thing. On that basis I was prescribed CPAP machine with set pressure 10 which didn't help at all (no sleep improvement).

Then a few months ago I did a WatchPAT test which yielded AHI = 46. This was requested by a neuropsychiatrist who asked my GP to refer me back to the respiratory department.

To be sure, my symptoms are consistent with severe OSA which tends to give the WatchPAT results more credence.

Anyway my question is: why the test discrepancy? I heard the WatchPAT is more sensitive than the standard test - is that true?

[SarcasticDave94]

When there's different test brands or types, it added variables to the test results. Different years can as well.

The test is also a one night snapshot of Apnea. If you were to look at your OSCAR charts, each night is a little different. You could in theory retest the sleep study every night for a year, and it'll give different numbers.

Which of these 3 is more accurate? I don't know. Do you feel like your untreated AHI is closer to 8 or 46?

[THEVGE]

Without showing the reports hard to say anything useful.....