Calcium24hurmscnc
A 24-hour urine calcium test measures the amount of calcium excreted in urine over a 24-hour period to help diagnose calcium metabolism disorders.
{"This test collects all urine produced in 24 hours to measure calcium levels","It helps diagnose conditions like kidney stones, hyperparathyroidism, and bone diseases","Normal results vary but typically range from 100 to 300 mg per 24 hours","The test requires a special container and specific collection instructions","Certain foods and medications can affect test results"}
Key facts at a glance
- LOINC
- 35248-4
- Short code
- CAU24
- Synonyms
- Calcium 24h Ur-msCnc
- Category
- electrolyte
- Sample
- urine
- Container
- 24-hour urine collection container with or without preservative (HCl or acetic acid)
- 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
- ≥ 18 years
- Method
- Spectrophotometry (Arsenazo III method) or Atomic Absorption Spectroscopy (AAS)
- CPT
- 82340
- SNOMED
- 104171006
- Specimen volume
- Complete 24-hour collection, typically 1000-2000 mL
- Stability
- Refrigerated (2-8°C): 7 days; Frozen (-20°C): 30 days
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
The 24-hour urine calcium test is a diagnostic test that measures how much calcium your kidneys excrete in urine over a 24-hour period. Calcium is an essential mineral that plays crucial roles in bone health, muscle function, nerve transmission, and blood clotting. This test helps doctors evaluate how your body processes calcium and identify potential disorders.
Why is it ordered?
Your doctor may order this test if you have symptoms or conditions related to abnormal calcium levels, such as kidney stones, bone pain, muscle weakness, or fatigue. It is commonly used to evaluate parathyroid function, diagnose hyperparathyroidism, monitor patients with kidney disease, assess bone disorders like osteoporosis, and identify causes of recurrent kidney stones.
How to prepare for the test
Before the test, inform your doctor about all medications you are taking, as some drugs can affect calcium levels. You may be asked to stop certain supplements or medications temporarily. Your doctor may also provide specific dietary instructions, as calcium intake from food and drinks can influence test results. It is important to follow all pre-test instructions carefully.
How is the test performed?
The test requires collecting all urine produced over a 24-hour period. On the start day, you will begin by urinating into the toilet upon waking up, then collect all subsequent urine in a special container provided by the lab. Keep the container refrigerated or in a cool place. After exactly 24 hours, urinate one final time and add this to the container. Return the completed collection to the lab as instructed.
Understanding the results
Normal 24-hour urine calcium levels typically range from 100 to 300 mg per day, though reference ranges may vary by laboratory. High calcium levels (hypercalciuria) may indicate hyperparathyroidism, kidney stones, certain cancers, excess vitamin D intake, or use of certain medications. Low calcium levels (hypocalciuria) may be due to hypoparathyroidism, vitamin D deficiency, kidney disease, or malnutrition. Your doctor will interpret your results based on your overall health and other test findings.
Reference range
100-300 mg/24 hnot specified
Complete 24-hour urine collection on normal diet; avoid calcium supplements during collection period
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Does the 24-hour urine collection have to be exactly 24 hours?
Can I exercise during the collection period?
What happens if I forget to collect a urine sample?
Do I need to fast before this test?
Are there any risks or side effects?
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