Urinalysis shows small blood in urine, but no RBC. Isn't that the same thing? Further testing? CT scan of abdomen/pelvis was normal & CBC

Don't worry. perhaps under a microscope with the urine concentrated by a centrifuge a cell or two of blood may be seen or not. There may be blood cells that broke up. You have had a great work up..
Myoglobin. I believe taht myoglobin from the muscle can cause this result. you really need to ask the doctor who does all the tests what he thinks and frequently he will say he doesn't know. We do many tests and having abnormal results is common, but these results may not be at a level to be of clinical importance.