Urine Calcium Test: A Patient Guide to What It Is, Why It May Be Ordered, How It Works, and What Your Results Mean
A urine test that measures the amount of calcium excreted in your urine to help evaluate kidney function, bone health, and parathyroid gland activity.
{"Measures calcium levels in urine to assess kidney function and bone metabolism","Helps diagnose conditions like kidney stones, hyperparathyroidism, and bone disorders","Typically requires a 24-hour urine collection for accurate results","Results indicate whether your body is excreting too much or too little calcium","Often ordered alongside blood tests for comprehensive evaluation"}
Key facts at a glance
- LOINC
- 108014-2
- Short code
- CA U
- Synonyms
- Calcium Msmt Ur
- Category
- electrolyte
- Sample
- urine
- Container
- 24-hour urine collection container (plastic, graduated)
- Units
- not specified
- Ref low
- 100
- Ref high
- 300
- Critical range
- 6 not specified – 14 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Atomic Absorption Spectroscopy (AAS) or Spectrophotometry using Arsenazo III dye
- CPT
- 82340
- SNOMED
- 271636005
- Specimen volume
- Complete 24-hour collection, typical volume 1000-2000 mL
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 30 days
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
What is a urine calcium test? It measures the amount of calcium in a urine sample, so your doctor can see how much calcium your kidneys remove from your body and check for problems such as kidney stones or calcium balance issues.
A urine calcium test measures the amount of calcium present in your urine. Calcium is an essential mineral that plays crucial roles in bone health, muscle function, nerve transmission, and blood clotting. Your body carefully regulates calcium levels through a balance of absorption in the intestines, storage in bones, and excretion through the kidneys.
Why do I need this urine calcium test? Your doctor may order it if you have symptoms, a history of kidney stones, bone or thyroid concerns, kidney disease, medication effects, or blood calcium levels that do not match typical patterns.
Your healthcare provider may order a urine calcium test to: evaluate kidney function and detect kidney stones, assess parathyroid gland function, diagnose or monitor bone disorders such as osteoporosis or osteomalacia, investigate abnormal blood calcium levels, and monitor the effects of certain medications like diuretics or calcium supplements.
How is the urine calcium test performed? You may provide a spot urine sample in a clean cup at the office, or collect all your urine for 24 hours in a special container, following the instructions given by the laboratory or your care team.
The most common method is a 24-hour urine collection. You will receive a special container from your laboratory. On the day of collection, start by urinating into the toilet when you wake up. For the next 24 hours, collect all urine in the provided container, including the first morning urine on the second day. Keep the container refrigerated or in a cool place. Return the complete collection to the laboratory as instructed.
Understanding your urine calcium results means looking at your measured value compared with the lab's typical range, along with symptoms, diet, medications, and kidney or bone health. High or low calcium levels can have many causes, so discuss what the numbers mean with your doctor.
Normal urine calcium levels typically range from 100 to 300 mg per 24 hours, though reference ranges may vary by laboratory. High urine calcium (hypercalciuria) may indicate kidney stones, hyperparathyroidism, certain cancers, sarcoidosis, or excessive vitamin D intake. Low urine calcium (hypocalciuria) may suggest hypoparathyroidism, vitamin D deficiency, kidney disease, or malnutrition.
Reference range
100-300 mg/24 hnot specified
24-hour urine collection required; maintain usual diet and fluid intake; avoid calcium supplements if possible; refrigerate specimen
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The urine calcium test provides valuable diagnostic information for several conditions. In kidney stone disease, high urine calcium is a major risk factor for calcium oxalate stone formation. For parathyroid disorders, the test helps differentiate between primary hyperparathyroidism (high urine calcium) and hypoparathyroidism (low urine calcium). In bone diseases, abnormal calcium excretion can indicate metabolic bone disorders. The test also helps monitor patients on long-term lithium therapy, as lithium can affect calcium metabolism, and evaluates patients with unexplained hypercalcemia.
Frequently asked questions
Do I need to fast before the test?
Will the test be painful?
What can affect my test results?
How long does it take to get results?
Is a 24-hour collection always required?
Sources
- 1
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- 3
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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