The characteristics of the more common types of abnormal crystals are summarized in the table below.
| Leucine | Yellow | Metabolism |
| Tyrosine | Colorless–yellow | Liver disease (rare) |
| Cystine | Colorless | Cystine metabolism |
| Cholesterol | Colorless | Renal tubular disease |
| Bilirubin | Gold-orange | Increased bilirubin |
High doses of ampicillin, sulfonamide drugs, or other drugs may also result in urine crystal formation. It is important to check the patient's current medications when unusual crystals are found in the urine specimen.
