Types of Crystals Found In Human Urine and Their Clinical Significance

Urine contains many dissolved substances(solutes) that the body needs to eliminate as waste chemicals. These solutes can form crystals when the concentration of dissolved substances has increased or when the pH level is increasing in either acid or base. This condition of presence of crystals in the urine is known as crystalluria. Sometimes crystals are found in healthy people and other times they are indicators of organ dysfunction, the presence of urinary tract stones of a like composition (known as urolithiasis), or an infection in the urinary tract.

Normal Crystals Abnormal Crystals
1. Uric acid Crystals 1. Bilirubin Crystals
2. Calcium Oxalate Crystals 2. Cholesterol Crystals
3. Hippuric Crystals 3. Cysteine Crystals
4. Calcium Phosphate Crystals 4. Leucine Crystals
5. Triple Phosphate Crystals 5. Tyrosine Crystals
6. Calcium Carbonate Crystals 6. Sulfa Crystals
7. Ammonium Biurate Crystals 8. Indinavir Crystals

Crystals that are Normal in Urine

Uric acid Crystals

Uric acid crystals are of varying sizes and shapes, found in acidic urine. They resemble rhomboids, parallelograms, and rosettes in shape and are amber in color. Though they are seen in normal urine, are also an indicator of disease processes, such as acute uric acid nephropathy or urate nephrolithiasis.

Calcium Oxalate Crystals

Calcium oxalate crystals are found in individuals with acidic, neutral or alkaline urine. These crystals are colorless when viewed microscopically. There are two forms of the calcium oxalate crystal: the monohydrate and dihydrate form.
The monohydrate calcium oxalate crystal is described as the “picket fence” form. These dumbbells shaped crystals are common in ethylene glycol toxicity. The dihydrate form is octahedral or “envelope” shaped.

Hippuric acid Crystals

Hippuric acid crystals are found in acid, neutral, or slightly alkaline urine. These colorless crystals are prisms, plates, or needle-like in shape. These crystals are often conglomerated into masses.

Triple Phosphate Crystals or struvite

Triple phosphate crystals form in alkaline urine and are composed of magnesium, ammonium and phosphate. These are rectangular in shape or similar with the coffin lid. These are sometimes associated with a bacterial urinary tract infection caused by urea splitting bacteria.

Calcium Carbonate Crystals

Calcium carbonate crystals are yellow to colorless dumbells or spheres with radial striations, found in alkaline urine. They are usually large crystals and can be readily observed at low magnification.

Calcium Phosphate Crystals

These are colorless crystals having shape like blunt ended needles or prisms, rosettes. These crystals are found in neutral to alkaline pH.

Ammonium Biurate Crystals

Ammonium urate (or biurate) crystals generally appear as brown or yellow-brown spherical bodies with irregular protrusions resembling “throny-apples”. These are found in alkaline urine.

Amorphous Crystals

Amorphous urates are found in acid urine. These crystals may appear pink on gross analysis and yellow microscopically. These crystals appear as granules in the urine sediment.
Amorphous phosphates are found in alkaline urine. These granules are colorless microscopically.

Crystals that are abnormal in Urine

Bilirubin crystals

Bilirubin crystals are abnormal crystals in urine. They form from conjugated bilirubin and are needle-like to granular crystals that are yellow in color. They are frequently attached to the surface of cells. Bilirubin crystals are seen in several hepatic disorders.

Cholesterol Crystals

cholesterol crystal
These appear as colorless rectangular plates with a notch in one or more corners and are found in acidic urine. The appearance of cholesterol is associated with the Nephrotic Syndrome.

Cysteine Crystals

Cystine crystals are flat colorless plates and have a characteristic hexagonal shape with equal or unequal sides. They occur in acidic urine that are associated with an inherited disorder. Presence of cystine crystals represents a proximal tubular defect in amino acid reabsorption.

Leucine Crystals

These are Yellowish-brown spheres with concentric circles with radial striations found in acidic/neutral urine. Leucine crystals may be seen in liver disorders in which amino acid metabolism is impaired.

Tyrosine Crystals

Tyrosine crystals appear as colorless/yellow fine needles in acidic/neutral urine. Tyrosine crystals may be seen in tyrosinemia and in certain liver disorders in which amino acid metabolism is impaired.

Sulfanomide Crystals

These are flat needles, sheaves of small needles or as spheroids. Often brown in color. The presence of sulfanomide crystals usually indicates administration of the drug and not necessarily a pathological condition. However, their presence is also associated with kidney stone formation.

32 Comments on Types of Crystals Found In Human Urine and Their Clinical Significance

  1. Thank you Dhurba!! I am studying for the DHA exam for laboratory technician and i found this website so helpful!!! Thanks a lot!!!

  2. Ebnahmed Ze Agemjay // November 25, 2015 at 4:07 pm // Reply

    Thanks! Dhurba. it’s nice, short and precise valuable information.

  3. Imesh Ruwan kumara // November 26, 2015 at 12:28 am // Reply

    That is very useful letter. Thanks

  4. Refreshing

  5. chandra mouliswaran. // December 11, 2015 at 10:30 am // Reply

    superb.and moreover the important fundamental to be known. And .also post regarding the coombs test was also informative. And im more curious towards the next one

  6. very interested website

  7. why some crystals is not belong a disease?

  8. The immages are clear and the facts are precise

  9. Celestine Mulwa // June 4, 2016 at 3:31 pm // Reply

    smart work very nice sometimes we forget these things

  10. Thank u for this post…it’s an organized presentation with prominent pics.

  11. great reference to an organized urine sediment

  12. Saleem pasha // June 5, 2016 at 9:28 am // Reply

    Thanks bro

  13. mohanad dbes // June 9, 2016 at 5:24 pm // Reply


  14. it helped me

  15. Ivan Adrian peter osta // October 1, 2016 at 7:00 am // Reply

    Very good write-up,Dhruv.Hoping to read a lot more on this pages.Kudos!!??

  16. It helped a lot

  17. This is amazing and beautiful! Thank you for putting together these photos, I’ve shared on twitter 🙂

  18. Great minds great people. Keep up the good work

  19. Belay bakalo // January 21, 2017 at 7:38 am // Reply

    Thank you very much!!

  20. juhad abdulla // January 28, 2017 at 8:29 am // Reply

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  22. Fantastic resource
    -PA Student, 2nd year.

  23. Devendr Ahirwar // March 18, 2017 at 8:57 am // Reply


  24. Informative, helpfull

  25. Laura Moire, MD // April 27, 2017 at 9:50 am // Reply

    Thank you for the wonderful photos and notes! You have helped
    so many their studies and work!

  26. about good knowledge.lot thanks. we all updated news

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