I don't understand the question. If a patient has had a sleep study, their sleep apnea should no longer be undiagnosed.
Or, are you suggesting there are false negatives from sleep studies?
I have seen a doctor write that it was not unusual to need three or four nights in a sleep lab before an appropriate diagnosis of sleep-disordered breathing (SDB) was made.
I had my PSG purely by my asking for it. I had to ask my PCP twice, a year apart before the referral was made. I don't think the lack of response on the first request was due to conscious resistance but more that it was forgotten - maybe the importance wasn't strong enough on the doctor's mental "radar". In my own "brain fog", I did not followup with her until my next annual physical. When I did get the referral, my result was in the severe range - 32 AHI, and complex - OSA & CSA. When I asked for the test, I didn't really know what I was asking for or anything about the therapy or procedures involved. I just wanted to quit feeling tired and relief of other symptoms including waking up gasping with a racing heart and related nightmares. I have never fallen asleep at work or while driviing, but would fall asleep anytime I tried to watch a movie at home, for years.
BTW - Dr. Mallinger - what type of doctor are you and are you certified in sleep?