Carbidopa/Levidopa working is the best test for Parkinson’s. Trust that. The datscan is a good test, but it is fairly commonly mis-read. My first neurologist said it was inconclusive, my second one said it was definitive

Bottom line, if it works you should be on it!

I've had the same experience, its been very frustrating. Two year and 1/2 years ago I started with tremors on my right hand, then the stiffness and balance issues came along. My neurologist felt that I had PD with my first visit, but he did tests to rule out the other possibility, a brain tumor. Thankfully brain tumor was ruled out. I had a DatScan, like you it come out 'normal'. My neurologist had no answers for me so he told me if I still had symptoms to come back in a year. A year later my symptoms were worse. He put me on C/L and I saw a huge change! My gait improved and tremors pretty much stopped, just appeared if I was under stress or was due for another dose of C/L. Because it seems to be a rare thing to happen I've been reading all I can about the DatScan. What I have found is that it doesn't always detect early PD the other information I have gathered is that if C/L helps with your symptoms, then its a better indication that you do have PD then the DatScan. In other words, if your Dr thinks its PD instead of having the DatScan he/she can have you try C/L and if it helps, you have PD. For what it's worth, I was actually glad to see your post as I have not found anyone else with a similar situation. Not that you want to have PD, but it certainly is very frustration to have so many of symptoms and to be told its not PD, but lets see how you're doing in a year! Longest year of my life! Good luck to you finding some answers!