Hello doctors I need help. My father recently urinated blood, not microscopic but a gross hematuria. We admitted him in a tertiary hospital, and they ordered UTZ and stonogram, but the sad thing is they found nothing in the results, there was no stone seen, but still they give the impression of renal stone, due to manifestations indicative of stone. If the stone was too small that it couldn't be seen on imaging studies, how come my father still have gross hematuria. Is it possible that a stonogram and an UTZ cannot detect stone? Or they have wrong diagnosis. My father occasionally passed out clots in the urine.