I take 600 mg tegretol daily-have level checked every 6 months...sometimes its near 6.0 and sometimes around 11.0..why the difference?

Different factors: Levels aren't necessarily going to bethe same (or even close) from one draw to another due to different things such as different times of the day they were taken as well as whether or not you went at true"trough" level points or not. Other medications can alter tegretol levels. The Important thing is that the levels remain in the therapeutic range and that you are compliant with your schedule.

Timing is everything: This may be related to when you took your dose in relation to the blood draw, was it an hour after you took med (peak)or 12 hours after (trough).