Thank you for the information.
Based on your description, she seems to have blood in urine without any other symptoms. There are many possible cause of blood in urine (hematuria), some of the common causes are: Urinary tract infections, stone, Kidney disease, Cancer, Medications (Common drugs that can cause visible urinary blood include aspirin, penicillin, the blood thinners warfarin and heparin), Strenuous exercise. Most commonly, the causes are simple and minor like infection but still the exact cause of hematuria needs to be ruled out. It is god to know that she has visited her physician for physical exam and ultrasound. In many cases, serious of tests are required to pin point the exact cause of hematuria such as urine test, IVP, cystoscopy, ultrasound, or CT. It is not possible to predict the cause just on the basis of hematuria, further investigation is the only reliable way to make the final diagnosis, especially when there is no symptoms at all. Since she has some discomfort in her lower abdomen, that is the area for urinary bladder, so that may be the cause but you will have to wait for the test report before making any conclusion. I think her doctor will be discussing her test report tomorrow and any other investigations that may be required. I am not sure what kind of doctor she is visiting now, but it would be a good idea to have a follow-up from a urologist. At this point, I don't think there is any obvious reason to worry.
You can read more about renal ultrasound from this link:
Please let me know if you have any other question for me.