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Cystine Crystal Identification in Urine (Qualitative)

Published: August 9, 2026Updated: August 16, 2026

This test checks for the presence of cystine crystals in your urine, which may indicate a genetic condition called cystinuria.

Quick summary

["Cystine crystals can signal cystinuria, a rare but manageable genetic disorder affecting kidney function."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
59277-4
Short code
Cystine Cry Stone Ql XR diff
Synonyms
Cystine Cry Stone Ql XR diff
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-diffraction
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like kidney stones, frequent pain in your back or side, or if you have a family history of cystinuria. It’s also used to confirm a suspected diagnosis or monitor treatment progress.

What to Expect Before the Test

No special preparation is needed. You’ll provide a urine sample, typically collected in the morning. Avoid excessive fluid intake or certain medications that might affect crystal formation for 24 hours before testing.

What the Results Mean

Positive results for cystine crystals suggest cystinuria. Negative results mean no crystals were detected, but further testing may still be needed to rule out other conditions. Your doctor will discuss next steps based on your symptoms and lab findings.

Common Causes and Conditions

Cystinuria is caused by a genetic mutation that leads to abnormal reabsorption of certain amino acids, including cystine, in your kidneys. This can cause cystine crystals to form in urine, leading to kidney stones or urinary tract issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Urine Cystine Crystal Screening

Frequently asked questions

What symptoms might indicate this test was ordered?
Symptoms like recurrent kidney stones, persistent back or side pain, nausea, vomiting, or blood in urine could prompt this test. If you have a family history of cystinuria, your doctor may also recommend screening.
How is cystinuria typically treated?
Treatment focuses on preventing kidney stones, such as increasing fluid intake, dietary modifications (avoiding high-oxalate foods), and medications to dissolve crystals or reduce their formation. Regular monitoring is essential.
Can cystine crystals appear in urine without cystinuria?
While cystine crystals are strongly linked to cystinuria, other rare conditions or medications may cause similar findings. Your doctor will evaluate results alongside your medical history and symptoms to confirm a diagnosis.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy