Hello, I've urine body odor as well ; along with fecal odor and rotten egg odor.. I think I have all the bad smell but never fishy odor.
You said that your doctor did all the test, but I suggest you to do a Stool test and Helicobacter pylori test. If you have just urine smell it could be H Pylori . The urine odor is actually Ammonia , and H pylori could lead to this bad smell. It's important that you do these test so that you can known if you have any gastrointestinal infection. From a blood test you cannot see it.