Introductions of Common Urinary Crystals

Urinary crystals in urine during the routine examination can appear in the following steps- First request the patient to bring a urine sample. After the arrival of the sample/specimen in the clinical laboratory, take nearly 5 ml of urine. Centrifuge it and put a drop of the mixed sediment part on a clean and grease-free glass slide and place a coverslip over it.  Examine the whole 22- by 22-mm coverslip systematically with the low power objective) (10X ) and low light intensity. If any suspicious objects have appeared, examine them with the high dry objective (40X). Crystalline deposits in Urine Examination show various forms of Crystals with the following properties as shown in a table.

Identification Features, and Clinical Significance of Urine Crystals-

S.No.	Crystals Name	Identification Features	Clinical Significance
1.	Calcium oxalate	They are colorless crystals that may find in various shapes like octahedral, envelope, and dumbbell shapes.	Calcium oxalate crystals are present in diabetes mellitus, liver diseases, and chronic liver diseases.
2.	Urate Crystals or Uric acid Crystals	They show diamond rhombic or rosette form.	There is little clinical significance however they can be found in gout or during chemotherapy and kidney stones, acute febrile conditions, and chronic nephritis.
3.	Calcium Carbonate Crystals	They are variably sized crystals that frequently appear as large spheroids with radial striations while smaller crystals with round to ovoid shapes.	They show little clinical significance even though conditions like decreased urine volume or a condition that alkalinizes urine, such as a vegetarian diet, chronic diarrhea, urinary tract infections or certain medications. Increased calcium levels that are too high such as immobilization, overactive parathyroid glands, and bone metastases.
4.	Triple Phosphate Crystals	They ate colorless prisms with 3 to 6 sides and frequently with oblique ends.	Triple phosphate crystals are associated with chronic cystitis, enlarged prostate, and chronic pyelitis.
5.	Cholesterol Crystals	They look like clear long rectangles with cut-out corners.	Severe kidney disease or when a lymphatic vessel has ruptured into the renal pelvis
6.	Ammonium biurate Crystals	They are yellow-brown spherical bodies with or without long, irregular spicules.	Ammonium biurate crystals are only clinically significant if they are found in fresh urine.
7.	Amorphous Urates	They appear as brown or yellow-brown spherical bodies with irregular protrusions also called thorn apples.	They have no clinical significance.
8.	Amorphous Phosphates	They appear as brown or yellow-brown spherical bodies with irregular protrusions also called thorn apples.	They have no clinical significance.
9.	Magnesium ammonium phosphate (struvite)	They are often colorless, rectangular prisms.	They are typically found in urinary tract infection (UTI) patients.
10.	Bilirubin	They are needle-like, granular in appearance, and often very small and yellow in color.	They appear in liver disease or poor liver function.
11.	Cystine Crystals	They are amino acids and they are often shaped like hexagons and may be colorless.	They are responsible for urine crystals and kidney stones.
12.	Tyrosine	They are colorless and needle-like in appearance and are often found in acidic urine.	They are found in liver disease or tyrosinemia.

Keynotes on Urine Crystals

• Amorphous urate is seen in acidic urine while amorphous phosphate is found in alkaline urine.
• Indinavir is a drug used to treat HIV that can cause the formation of crystals in the urine.
• Urinary crystals that aren’t created by underlying conditions like liver disease or genetic disorder can often be prevented. In some cases, even crystalluria activated by genetic causes can be reduced with lifestyle or diet changes.
• Drinking more water and staying hydrated helps reduce the chemical concentrations in the urine, preventing crystals from forming.

Gallery of Urinary Crystals

Calcium oxalate monohydrate crystals

Calcium oxalate

Urate Crystals or Uric acid Crystals in Urine Microscopy

Calcium carbonate crystals

Triple phosphate (ammonium magnesium phosphate) crystals in urine

Cholesterol Crystals

Ammonium biurate Crystals

Amorphous Urate in Urine Microscopy

Amorphous phosphate in Urine Microscopy