Crystals in Urine (Crystalluria): What a Lab Finding Means, Causes, Treatment and Prevention — What You Need to Know
Updated: 59 minutes ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
Quick Answer: Crystals in urine (crystalluria) form when there are too many minerals in your urine and not enough liquid, causing tiny pieces to collect into masses. The finding often shows up on a routine urine test (urinalysis) and frequently means nothing at all — it does not always indicate an infection or disease. Some crystals, however, can grow into stones that block the urinary tract, and blockages can cause serious problems such as acute kidney injury (AKI). Common causes include dehydration, diet, certain medications, urinary tract infections, ethylene glycol poisoning, and tumor lysis syndrome. Treatment usually means drinking more water or adjusting diet and medications, and prevention centers on fluids, healthy weight, moderate protein, and less salt and sugar.
TL;DR
Crystalluria means crystals are present in your urine, usually found on a urine test. Most crystals are harmless, especially when you are well hydrated, but some types signal inherited disorders (cystine and xanthine) and some can grow into stones that block urine flow and harm the kidneys. A laboratory identifies the crystal type by its shape under a microscope, and treatment follows the cause — often simply more water, less salt and sugar, or a medication change.
Important limitation: the referenced medical source contains no prevalence or incidence statistics, so no figures are quoted here; this content is not a substitute for professional medical advice.
What Is Crystalluria?
Crystals in urine occur when there are too many minerals in your urine and not enough liquid. The tiny pieces collect and form masses.
These crystals may be found during urine tests (urinalysis). Having crystals in your urine is called crystalluria.
Some crystals don't cause problems. Others can get big and form stones that get stuck in parts of your urinary tract and cause blockages. Blockages can cause serious problems, like acute kidney injury (AKI), which is also called acute renal failure (ARF).
What are the common types of crystals found in urine?
Types of crystals that a lab tech might see in your urine include:
Crystal type | Notes |
Ammonium biurate | One of several types a lab may report |
Bilirubin | A crystal formed from bilirubin |
Calcium oxalate or calcium phosphate | Among the most commonly reported types |
Cystine | Indicates a rare inherited disorder |
Hippuric acid | Identified by shape under a microscope |
Leucine | Identified by shape under a microscope |
Struvite (magnesium ammonium phosphate) | Associated with urinary tract infections |
Tyrosine | Identified by shape under a microscope |
Uric acid | Associated with gout and high purine load |
Xanthine | Indicates a rare inherited disorder |
The laboratory test can identify the type of crystals by the shape of the crystals under a microscope. Some of the crystals may have no identifiable shape (amorphous).
The pH (acidity) of your urine can contribute to the type of crystals that happen.
Who gets crystals in their urine?
Anyone can have crystals in their urine. The presence of crystals doesn't always mean that you have some type of medical condition, though, except in the case of cystine and xanthine. These crystals indicate rare inherited disorders.
People who are prone to developing kidney stones also may have crystals evident in their urine.
How does crystalluria affect the body?
You might have crystals in your urine that really don't mean anything. Others can cause problems, like kidney stones.
When crystals collect into bigger masses, they can block urine from leaving your body. Some crystals can pass through your urinary tract and out of your body on their own, while others may need to be removed from your body by a healthcare provider.
What Causes Crystals in Urine?
There are many things that can cause crystals to form in urine. They include:
Cause | How it contributes |
Dehydration | Not drinking enough water leaves too many minerals and too little liquid |
Diet | Eating large amounts of certain foods, including protein, salt, fruits and vegetables |
Medications | Such as amoxicillin, acyclovir, sulfonamides, atazanavir and methotrexate |
Urinary tract infections | Infections change urine chemistry |
Ethylene glycol poisoning | A toxic ingestion that promotes crystal formation |
Tumor lysis syndrome | The death of a large number of cancer cells, which may happen as a result of cancer treatment |
Is crystalluria contagious?
No, crystalluria isn't contagious. Even if you have a urinary tract infection, you're not contagious.
What Are the Signs and Symptoms of Crystals in Urine?
You may not have any signs or symptoms of crystals in urine. If you do, they might include:
Symptom | What it looks like |
Pain | Discomfort from stones or blockage |
Fever | Elevated body temperature |
Cloudy or foamy urine | Visible change in urine appearance |
Urinating more often than usual | Feeling like you have to pee more frequently |
Bloody urine (hematuria) | Blood in the urine |
Bad-smelling urine | Unusual or strong urine odor |
When to see your healthcare provider
You should contact your healthcare provider if you have pain or fever along with changes in your urine. Kidney stones and other stones, like ureteral stones, can be very painful. They can also cause toxins to stay in your system and cause problems.
Seek prompt care if urine flow stops or you cannot pass urine, because blockages can lead to acute kidney injury (acute renal failure), a serious problem.
How Are Crystals in Urine Diagnosed?
Your healthcare provider may order urine tests as part of your annual exam or as a result of symptoms you report. The urine samples will be examined in the lab. You may need other tests if your healthcare provider needs to order them to diagnose your condition correctly.
The laboratory identifies the crystal type by the shape of the crystals under a microscope, and some crystals have no identifiable shape (amorphous). Your urine's pH (acidity) can contribute to which type of crystals form.
How Do You Treat Crystals in Urine?
Treatment depends on the cause of the crystals. In many cases, you may just need to drink more water or cut back on your consumption of certain foods or things found in foods, like salt and sugar.
If the crystals are a result of taking certain medication, your healthcare provider might be able to switch your medication or dosage. If the crystals point to some type of disease, then your healthcare provider will treat that condition.
Treatment path | What it involves |
Hydration | Drink more water |
Diet changes | Cut back on certain foods or things found in foods, like salt and sugar |
Medication review | Provider might switch your medication or dosage if it is the cause |
Treating the underlying disease | If crystals point to a disease, the provider treats that condition |
Stone removal | Some stones may need to be removed by a healthcare provider if they block urine flow |
What Is the Outlook If I Have Crystals in My Urine?
The outlook if you have crystals in your urine is probably very good. This does depend on any other conditions being treated.
How Can You Reduce Your Risk of Crystals in Urine?
You can lower your risk of developing crystals in your urine and stones in your urinary tract if you:
Prevention step | Details |
Drink adequate fluids | Like water |
Maintain a healthy weight | Reach and maintain a healthy weight |
Moderate your protein | Eat only a moderate amount of protein |
Get guidance on minerals and vitamins | Work with your healthcare provider or a registered dietitian to figure out how much calcium, oxalate and vitamin C you should have to be healthy |
Cut back on processed foods | Eat fewer processed foods to cut down on salt and sugar intake |
Living With Crystalluria: Practical Notes
Most people with crystalluria simply benefit from drinking more fluids and keeping their urine well diluted. If you have been told you are prone to kidney stones, the same prevention steps — fluids, healthy weight, moderate protein, and lower salt and sugar — help lower the risk of both crystals and stones.
When to See a Healthcare Provider
Contact your healthcare provider if you have pain or fever along with changes in your urine, or if a urine test reports crystals and you are unsure what they mean. Seek prompt care for blocked urine flow, since blockages can cause acute kidney injury.
A note from the referenced medical source: "Crystalluria, or having crystals in your urine, is relatively common. Crystals can be found in the urine of people who are completely healthy and in the urine of people who have some type of illness. They might be found on a routine urine test or if your healthcare provider suspects another condition. One of the best ways to prevent crystals from developing is by drinking enough fluids."
Conclusion: The Bottom Line
Crystals in urine are a common laboratory finding that usually reflects concentrated urine — too many minerals and too little liquid. In most cases they mean nothing and pass on their own. The exceptions are cystine and xanthine crystals, which point to rare inherited disorders, and crystals that grow into stones that can block the urinary tract and, in serious cases, cause acute kidney injury. If crystals appear, the next step is to find the cause — dehydration, diet, medication, infection, poisoning, or tumor lysis syndrome — because treatment follows the cause. Drink plenty of fluids, keep salt, sugar and protein in moderation, maintain a healthy weight, and contact your provider for pain or fever with urine changes.
Next step: If a recent urine test showed crystals, or you have pain, fever, or changes in your urine, book an appointment with a healthcare provider to review your results and decide whether any treatment or diet changes are needed.
FAQ
What does it mean to have crystals in your urine?
Crystals in urine occur when there are too many minerals in your urine and not enough liquid. The tiny pieces collect and form masses. Having crystals in your urine is called crystalluria.
Is crystalluria dangerous?
Usually no. You might have crystals in your urine that really don't mean anything. But others can form stones that block the urinary tract, and blockages can cause serious problems like acute kidney injury (AKI), also called acute renal failure (ARF).
What are the common types of urine crystals?
A lab tech might see ammonium biurate, bilirubin, calcium oxalate or calcium phosphate, cystine, hippuric acid, leucine, struvite (magnesium ammonium phosphate), tyrosine, uric acid, and xanthine.
How does a lab identify the crystal type?
The laboratory test identifies the type of crystals by the shape of the crystals under a microscope. Some crystals have no identifiable shape (amorphous).
What role does urine pH play?
The pH (acidity) of your urine can contribute to the type of crystals that happen.
Which crystals indicate an inherited disorder?
Cystine and xanthine crystals indicate rare inherited disorders. For all other types, the presence of crystals doesn't always mean you have a medical condition.
Can crystals cause kidney stones?
Yes. Crystals can get big and form stones that get stuck in parts of your urinary tract and cause blockages. People who are prone to developing kidney stones also may have crystals evident in their urine.
Can crystals pass on their own?
Some crystals can pass through your urinary tract and out of your body on their own, while others may need to be removed from your body by a healthcare provider.
What are the symptoms of crystals in urine?
You may not have any signs or symptoms. If you do, they might include pain, fever, cloudy or foamy urine, feeling like you have to pee more often than usual, bloody urine (hematuria), and bad-smelling urine.
What causes crystals to form in urine?
Causes include dehydration (not drinking enough water), eating large amounts of certain foods including protein, salt, fruits and vegetables, certain medications (amoxicillin, acyclovir, sulfonamides, atazanavir, methotrexate), urinary tract infections, ethylene glycol poisoning, and tumor lysis syndrome.
Which medications can cause crystals in urine?
Medications such as amoxicillin, acyclovir, sulfonamides, atazanavir and methotrexate.
What is tumor lysis syndrome?
A condition caused by the death of a large number of cancer cells, which may happen as a result of cancer treatment. It can cause crystals to form in urine.
What is struvite?
Struvite is magnesium ammonium phosphate, one of the crystal types a lab tech might see in your urine.
Is crystalluria contagious?
No, crystalluria isn't contagious. Even if you have a urinary tract infection, you're not contagious.
How are crystals in urine diagnosed?
Your healthcare provider may order urine tests as part of your annual exam or from symptoms you report. The urine samples are examined in the lab, and the crystal type is identified by shape under a microscope. You may need other tests to diagnose your condition correctly.
How are crystals in urine treated?
Treatment depends on the cause. Often you just need to drink more water or cut back on certain foods or things found in foods, like salt and sugar.
What if a medication is causing the crystals?
Your healthcare provider might be able to switch your medication or dosage.
What if crystals point to a disease?
If the crystals point to some type of disease, your healthcare provider will treat that condition.
What is the outlook for crystalluria?
The outlook is probably very good, though it depends on any other conditions being treated.
What is acute kidney injury (AKI)?
A serious problem that can result from blockages when crystals collect into bigger masses and block urine from leaving your body. AKI is also called acute renal failure (ARF).
Can ethylene glycol cause crystals?
Yes. Ethylene glycol poisoning is one of the causes of crystals forming in urine.
How can I prevent crystals in my urine?
Drink adequate fluids like water, reach and maintain a healthy weight, eat only a moderate amount of protein, work with your provider or a registered dietitian on how much calcium, oxalate and vitamin C to have, and eat fewer processed foods to cut down on salt and sugar.
When should I contact my healthcare provider?
You should contact your healthcare provider if you have pain or fever along with changes in your urine. Stones can be very painful and can cause toxins to stay in your system.
Can I have crystals without any symptoms?
Yes. You may not have any signs or symptoms of crystals in urine.
Who can get crystalluria?
Anyone can have crystals in their urine. They may be found in healthy people and in people with some type of illness, on a routine urine test or when a provider suspects another condition.
External References
References
Medical Disclaimer
This content is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions about a medical condition. Never disregard professional medical advice or delay seeking care because of something you have read here.
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