Well, I think that I am going to split the difference on this dispute. As a health care professional in the sleep field, I am asked to base treatment decisions based upon the data from both types of studies. There is no question that you get a more complete picture from the actual in-lab sleep study. I am always glad to see an actual in lab test because it makes my job easier. Having said that, I find that a good quality HST usually is sufficient to screen for OSA and CSA, if only barely so. I would not underestimate the value of having a sleep technician present in the room to observe you all night. The biggest issue is that they can tell if you are ACTUALLY asleep which is always speculative with an HST. As the original poster said, there are a number of other sleep disorders that become evident in a lab test, so that the diagnostic data is much richer. However, in defense of Sierra's position, a lot of patients find a lab-based test either too much to cope with or too expensive and would simply fail to address their problems if not for the more simplified HST route. In that sense, the HST is a boon. Probably, the whole question will be moot soon because the insurance companies, which are always out to save money at the patient's expense, are increasingly unwilling to pay for the lab test anyway. But make no mistake about it, if you patients want the VERY BEST for yourself diagnostically, the lab test is still IT. Arthur B. Luisi, Jr., D.M.D.. The Naples Center For Dental Sleep Medicine.