Crystals must be identified in the urine sediment. The MLT must be able to differentiate between normal crystals frequently encountered in the urine and "abnormal" crystals whose appearance is pathological in nature. Note: The pH at which a fresh urine sample is at aids in the identification of a crystal. All abnormal crystals precipitate in the urine at acidic pHs. Read more: Urinalysis: Crystals - UOIT Clinical Biochemistry Source: UOIT Clinical Biochemistry