Negative for Methadone??

[WinnieSue]

I have been taking Methadone for a long time. Over the last few years, there has been a total of 4 times now that I have come up NEGATIVE for Methadone. I take it everyday, I don't share it, or sell it or whatever you may be thinking. I am a larger woman and I am only on 15mg daily. The doctor at my clinic says this is impossible, and of course now I have to do urine tests in front of a nurse. Its frustrating to me that this has to happen, as over the 20 years, it has happened 4x. what are the chances that it will happen again while being watched. ? I mean 4x in 20 years is NOT alot. I have nothing to hide and have no problem testing in front of a nurse. But I know I've heard of this happening to others.   So frustrating...anyone else have negative methadone tests? any good reading material on this? there is nothing wrong with my liver - I just seem to metabolize it quicker.