Hi. I am familiar with the SDMA test, and very familiar with kidney disease. I understand you're panicked in relation to the SDMA number but what WAS her number? Also, this test is very new and data is still being collected. It is a tool in the toolbox in identifying dogs with early kidney disease or that are predisposed to it, but this test alone is not enough to offer significant data for a diagnosis. It is to be evaluated alongside bloodwork and a urinalysis and can give a more clear picture of how your dog's kidneys are functioning. So try not to get in a panic yet. Whatever the number was, if it was high enough to worry you, then a urinalysis is a good next step. When you do the urinalysis, I am sure your vet will want to test urine specific gravity (USG). The test will give info on how well your dog is concentrating her urine. The first pee of the day will be the most concentrated so try to catch that one.
Dogs with early kidney disease will have urine that is more dilute. It is good that you are taking the steps to rule out the kidney disease early though. Its a terrible diagnosis, and the peace of mind is priceless.
Diana