Crystals in urine occur when there are too many minerals in your urine and not enough liquid. The tiny pieces collect and form masses. These crystals may be found during urine tests (urinalysis). Having crystals in your urine is called crystalluria.
Some crystals don’t cause problems. Others can get big and form stones that get stuck in parts of your urinary tract and cause blockages. Blockages can cause serious problems, like acute kidney injury (AKI), which is also called acute renal failure (ARF).