Uric acid crystals only show up when the urine output is very low, partly because the crystals are concentrated and partly because the acid milieu changes their structure so that they are red. If this baby is not getting much reduced milk, then it is unlikely these are uric acid crystals. How does the doctor know this is not blood? That would be my first thought if the baby is otherwise doing well. We probably have at least two weights, I hope, since she saw the doctor twice. If the weight is also up, the baby cannot be dehydrated. Jack Newman, MD, FRCPC