Question about edema testing

Just recently I have noticed that I had swelling in my lower legs just above my ankle,I went to the doctor and he gave me some mild diuretic.He told me to only take them as needed,so I took 1 a day for about a week and the swelling went down very quickly,so I stopped taking them for about a week and now the swelling has come back.The doctor wanted me to go for some tests at the lab,I think one was for diabetes blood Sugar and I'm not sure about the other one,but they were both blood tests and I am just terrified of needles,so I didn't go for the tests,I was wondering if someone knew of any other way that you can be tested without getting a needle?I was also wondering if anyone knows of a really good natural diuretic that I could take instead of going back to the doctor and getting a perscription?I live in Canada so I don't know what is available here at the health food stores,it seems that all the stuff that works great is only available in the U.S.A.Thanks and I hope that someone has some advice that can help me!!