I had bloodwork done as well, all came back normal. I don’t know of any other tests that your doctor can do for this issue. Wouldn’t hurt to ask I suppose. I saw a dermatologist and he said it’s skin thinning as we age. He told me to use Arnica cream/gel which I have been using, it helps heal bruises but no matter what I’ve tried nothing has prevented them. I recently purchased Dermend and thought I’d give it a try. Some of the ladies here have said to use it continuously to help prevent sever bruising. I’ll see if it helps. Your photo looks like the bruises I get. My skin also tears easily. I’ve shared a photo of how bad my arms have gotten at times, not pretty!