Crystals in Urine

Urine is basically water that contains dissolved substances (solutes) - waste products of an organism. These soluts may settle down as crystals if the urine is allowed to stand for a long time. Crystals in the urine is known as crystalluria. Sometimes crystals are found in healthy people and other times they are indicators of some problems with urinary tract.

If only one test shows small amounts of crystals with no other abnormalities being found, this test may be considered of no diagnostic value. Generally, elevated levels of crystals in the urine do not mean the urine contains high concentrations of solutes because this may be caused by changes in the colloidal composition of the urine and its pH, as well as by eating certain foods. If so, elevated levels of crystals in the urine are of no diagnostic value. Significant amounts of crystals found in the urinary sediment on a regular basis may be an indicator of renal or gastrointestinal tract disorders. Elevated levels of crystals in the urine could be a factor increasing one’s risk of developing kidney stones and urolithiasis.

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Crystals are often found in the urine of children due to, above all, their diet or their kidneys’ reduced ability to dissolve large amounts of solutes.

Urinary pH plays an important role in crystals formation. Normally, our urine is slightly acidic, while pH fluctuations may cause crystals to settle down. Uric acid crystals and its salts (urates) often settle down in acidic urine. Thorn-apple crystals, calcium carbonate crystals, amorphous phosphates and magnesium ammonium phosphates form in alkaline urine. Oxalates may form in both acidic and alkaline urine.

If crystals come from the solutes that are normally found in the urine, they are regarded as normal crystals. Most often, oxalates, urates and phosphates form in urinary sediment. Crystals in the urine that are not from usual solutes are regarded as abnormal crystals (tyrosine, cystine, leucine) and may indicate an abnormal metabolic process.

High levels of urate crystals in urine may be caused by certain medicines (diuretics, vitamin C, lower doses of aspirin, etc.); eating foods that are very high in purines: organ meats (liver, brains), red meats (beef, lamb), game meat (deer, elk), and some seafood (sardines, herring, scallops); drinking not enough fluids or losing too much fluid; drinking a lot of alcohol, especially beer.

If large amounts of urates are found in the urine, it is recommended that the patient increases the amount of daily water intake to 2.5 liters and follows a low-purine diet. It is healthy for such patients to drink alkaline mineral water and eat foods high in calcium, magnesium, zinc, vitamin A and group B vitamins.

The presence of oxalate crystals in urine mostly occurs in normal individuals. Oxalate crystals most often appear in the urine due to eating foods rich in oxalic acid and vitamin C (sorrel, rhubarb, spinach, parsley, celery, radishes, beets, citrus).

The appearance of oxalate in the urine can be a sign of congenital metabolic oxalic acid, which can manifest inflammatory diseases of the kidney and urolithiasis. Oxalate crystals can damage the mucous membrane, causing microhematuria and irritation of the urinary tract.

Oxalates may be found in the urine in pyelonephritis, diabetes, inflammatory bowel disease, ulcerative colitis. To reduce the amount of oxalate crystals in the urine it is recommended to increases the amount of daily water intake to 2 liters, eat foods high in magnesium (dark green vegetables, legumes, cereals, nuts, wheat bread, and fish) and group B vitamins, especially B6.

Phosphates may be found in the urine of healthy individuals after eating a large meal due to the urine’s decreased acidity. High levels of phosphate in the urine may be caused by eating a meal high in phosphorus (fish, eggs, milk, dairy products, oatmeal, barley, buckwheat, alkaline mineral water). High levels of phosphate in the urine may also be due urinary tract infections, too much vitamin D in the body, an overactive parathyroid gland, vomiting, fever.

If phosphates are found in the urine, limit your intake of the foods high in calcium and vitamin D.

Calcium oxalate crystals

Crystals in Urine

Calcium oxalate crystals are the most common cause of kidney stones. These crystals are formed from oxalate and calcium. Oxalate is a natural end product of metabolism in the body. Elevated levels of oxalate in the body can be caused by eating foods rich in oxalate, including fruits, vegetables, beans, nuts, seeds, chocolate, and tea. Some examples of products containing oxalate include spinach, rhubarb, peanuts, beets, coffee, oranges, cranberries, etc.

Calcium oxalate crystals can form in the urine due to:

  • insufficient fluid intake (dehydration)
  • eating a lot of products that contain high levels of oxalate, protein, salt

In addition, some diseases can contribute to the formation of calcium oxalate crystals and the formation of stones:

  • obesity
  • hyperparathyroidism (a very large amount of parathyroid hormone in the blood causing calcium loss)
  • Dent disease (a rare genetic disease that affects the kidneys)
  • inflammatory bowel disease (ulcerative colitis, Crohn's disease)

Urinalysis (UA) Interpretation