Urinalysis - The Carter Center

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Some drug crystals in the urine include, sulfonamides,
aspirin, caffeine, used to follow the treatment condition.
I. Acidic Urine Crystals
a. Amorphous Urates (Anhydrous uric acid)
- Normally present in urine in different quantity.
- Have pink to “brick red” color.
- From very small granules and seen in cluster.
- Dissolve in urine when the sample is gently heated.
- When urine is left in the refrigerator, it shows heavy
precipitation of urates.
b. Uric Acid Crystals
- Polymorphs (different in shape) i.e. square, prism,
hexagonal, rostelles etc.
- Yellow to yellow brown in color.
- Size is 30-150 μm
- Small quantity found in normal urine, but increases in
association with:
- Increased Purine metabolism in case of gout.
- Increased Nucleic Acid turn over, such as leukemia.
c. Cystine Crystals
- Rarely found.
- Flat, hexagonal plates with well defined edges.
- Colorless, and highly retractile.
- Size is 30-60 μm.
- Found only in fresh urine, because if there is delay, they
are soluble and not seen.
- Appeared during cystinosis, which is a hereditary disease
(Wilson disease), or during transient acute phase of