Understanding Your Diagnostic Test and What the Results May Mean
A test that measures the amount of calcium in your urine over a 24-hour period to help diagnose kidney stones and bone disorders.
{"Measures calcium excreted in urine over 24 hours","Helps diagnose kidney stones, hyperparathyroidism, and bone diseases","Requires collecting all urine in a special container for 24 hours"}
Key facts at a glance
- LOINC
- 25362-5
- Short code
- U-Ca 24h
- Synonyms
- Calcium 24h Ur-sCnc
- Category
- electrolyte
- Sample
- urine
- Container
- 24-hour urine collection container (plastic or glass), with or without 10 mL 6N HCl preservative
- Units
- not specified
- Ref low
- 1
- Ref high
- 7.5
- Critical range
- 6 not specified – 14 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Atomic absorption spectroscopy (AAS) or spectrophotometric method using arsenazo III dye
- CPT
- 82340
- SNOMED
- 271577006
- Specimen volume
- Minimum 10 mL from well-mixed 24-hour collection; record total volume
- Stability
- Room temperature: 7 days; Refrigerated (2-8°C): 14 days; Frozen (-20°C): 30 days
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
What is this test? This diagnostic test is used to evaluate a specific health concern, measure body functions, or help your healthcare professional identify, monitor, or rule out a medical condition.
The 24-hour urine calcium test measures how much calcium your kidneys filter out and excrete in your urine over a 24-hour period. Calcium is an important mineral that keeps your bones strong, helps your muscles work, and supports nerve function. Normally, your body carefully balances calcium levels by absorbing it from food, storing it in bones, and excreting excess amounts through urine.
How is the test done? Depending on the type of test, a healthcare professional may collect a blood, urine, or tissue sample, perform a physical measurement, or use specialized equipment to obtain the needed information.
You will receive a special container from your healthcare provider. For 24 hours, you must collect all your urine in this container. This includes the first urine of the day (which you may discard), and then every urine sample throughout the day and night, including the first urine of the next morning. Keep the container refrigerated or in a cool place. Label it with your name, the date, and the start and end times. Return the container to your lab as instructed.
Why might I need this test? Your healthcare professional may recommend this test because of symptoms, a routine checkup, an abnormal finding, a known medical condition, treatment monitoring, or the need to assess your overall health.
Your doctor may order this test if you have symptoms of kidney stones (such as severe back or abdominal pain, blood in urine), signs of hyperparathyroidism (fatigue, weakness, depression), or to monitor bone diseases. It may also be used to check how well your body is absorbing calcium or to monitor certain treatments.
What do the results mean? Results are interpreted using the test method, reference ranges, your symptoms, medical history, and other findings, so an abnormal result does not always indicate disease and should be discussed with your healthcare professional.
High urine calcium (hypercalciuria) may indicate kidney stones, hyperparathyroidism, certain cancers, excessive vitamin D intake, or use of diuretics. Low urine calcium (hypocalciuria) may be due to vitamin D deficiency, kidney disease, or hypoparathyroidism. Your doctor will interpret your results based on your symptoms, diet, and other test results.
Reference range
1.0-7.5 mmol/Lnot specified
24-hour urine collection required; discard first morning void, collect all subsequent urine for 24 hours including next morning void; refrigerate during collection; maintain usual diet unless otherwise instructed
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is primarily used to evaluate calcium metabolism disorders. It helps identify the cause of kidney stones, which affect about 10% of adults and often contain calcium. The test also aids in diagnosing hyperparathyroidism, where the parathyroid glands produce too much hormone, causing elevated calcium levels. In bone diseases like osteoporosis, this test helps assess whether bones are releasing too much calcium. Additionally, it monitors patients on certain medications that affect calcium levels.
Frequently asked questions
Does diet affect the test results?
What happens if I forget to collect a urine sample?
Is the test painful?
How long does it take to get results?
Sources
- 1
- 2
- 3
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.
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