Uric Acid Crystals in Urine

Uric Acid Crystals

Since about 75% of uric acid is excreted from the body via the kidneys, uric acid crystals are often found in morning urine during microscopic examination. These crystals appear when the urine pH is acidic (below 6). They do not hold particular clinical significance unless there is also an elevated level of uric acid in the blood. Such findings may indicate gout, which involves the accumulation of uric acid crystals in the joints. The presence of uric acid crystals in urine is considered pathological only if they are detected in fresh urine (immediately after urination). The detection of these crystals, alongside a larger number of epithelial cells, may suggest the formation of kidney stones or nephropathy in the case of gout.

Appearance of Uric Acid Crystals

Uric acid crystals vary in size and shape. Their color can range from whitish (colorless forms) to dark yellow or brown. They often appear as multilayered plates with sharp edges, in prismatic, rhombic, rosette-like, or oval shapes.

What is Uric Acid and How is it Produced?

Uric acid is produced in the body through the breakdown of purine bases obtained from food. The resulting uric acid is further metabolized in the liver and excreted via the kidneys. However, if uric acid levels exceed normal limits, uric acid crystals can form and deposit in the joints, urinary tract, or kidney tissue. The symptoms and complications resulting from this condition can vary and may pose a minor or more serious health issue for many individuals.

Diet and Uric Acid

Diet has a significant impact on the formation and quantity of uric acid crystals in urine (as well as uric acid levels in the blood). Elevated uric acid levels in the blood are often caused by diets rich in purine bases.
Foods rich in purine bases include:

• Red meat, especially organ meats
• Anchovies
• Seafood
• Alcohol, particularly beer and red wine
• Carbonated drinks

Uric Acid Crystals and Chemotherapy

The presence of uric acid crystals in urine is also directly related to the breakdown of nucleic acids. For this reason, an increased amount of these crystals can be expected in the urine of oncology patients undergoing chemotherapy (those suffering from lymphoma or leukemia).