This is Dr David
I am another expert here.
I'm glad you have seen a nephrologist already.
BUN/creatinine ratios area really only meaningful if you have a known kidney disorder already.
it doesn't sound like you have anything wrong with your kidneys
microscopic blood in the urine can be from small microscopic kidney stones in your system or mild inflammation in your kidneys.
sometimes even after menopause, vaginal atrophy can cause thinning of the urethra lining and vaginal lining which can make bleeding easier into the blood.
after childbirth the urethra lining can become thinner as well can cause some small trace blood to be in the urine.
if your nephrologist is not worried about your kidneys, I would not stress.
vomiting and increased chest and abdominal pressure from vomiting itself can put more pressure on the urethra and bladder linings and cause bleeding.
what is better than a scan is a cystoscopy procedure by a urologist to look up into the urethra and bladder.
a cystoscopy can see small blood vessel abnormalities on the wall of the bladder which often can cause small microscopic blood
these can be burned with electrocautery to stop the bleeding
let me know if you have other questions.
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