sick cat

I have a ten year old male DSH cat and he has diabetes, and he was having trouble breathing it was discovered that he had a fluid build up in his chest cavity and was drained and seemed to feel beter. The fluid was tested and nothing was conclusive to be the cause He is now on Glucobay and Lasix but is still experiencing breathing issues. I have had him drained twice but there hasn't been much fluid. I was reading on line that heartworms could be the problem. Do you think I should have the blood tests done to determine this?

Any coughing at all? Is he lethargic?

According to the Ontario Veterinary Medical Association 1-3 cats are diagnosed with heartworm every year but other made have contracted it without their owners knowing since the signs are less restricted than with dogs. http://www.ovma.org/pet_owners/cats/heartworm_in_cats.html

If you think your cat may have been exposed it's worth the few dollars for the test.