Quick Review Cards for Medical Laboratory Science

Normal Crystals Found in Acid or Neutral

Urine

Urinalysis and Body

Fluids Review 502

CRYSTAL DESCRIPTION COMMENTS

Amorphous urates

Uric acid

Calcium oxalate

Form pink precipitate in bottom of tube. May

obscure significant sediment. Dissolve by

warming to 60ºC.

Birefringent. Polarizes light.

Occasionally found in slightly alk urine. Mono-

hydrate form may be mistaken for RBCs. Most

common constituent of renal calculi. From

oxalate-rich foods.

Irregular granules.

Pleomorphic. 4-sided, 6-sided, star-shaped,

rosettes, spears, plates. Colorless, red-brown,

or yellow.

Octahedral (8-sided) envelope form is most

common. Also dumbbell & ovoid forms.

From Strasinger SK, Di Lorenzo MS. Urinalysis and Body Fluids, 5th ed. Philadelphia: FA Davis; 2008:113.