Calcium12hurmcnc
A test that measures the amount of calcium in your urine collected over a 12-hour period to evaluate calcium metabolism and kidney function.
{"Measures calcium levels in urine collected over 12 hours","Helps diagnose kidney stones, parathyroid disorders, and bone diseases","Requires complete urine collection - do not miss any samples","Results are affected by diet, medications, and kidney function","Follow your healthcare provider's instructions for collection carefully"}
Key facts at a glance
- LOINC
- 57335-2
- Short code
- UCA12
- Synonyms
- Calcium 12h Ur-mCnc
- Category
- electrolyte
- Sample
- urine
- Container
- 24-hour urine collection container with preservative (typically HCl or thymol)
- Units
- not specified
- Ref low
- 50
- Ref high
- 150
- Critical range
- 6 not specified – 14 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Spectrophotometry (o-cresolphthalein complexone method) or Atomic Absorption Spectrometry
- CPT
- 82340
- SNOMED
- 313295009
- Specimen volume
- 10-50 mL aliquot from 12-hour collection
- Stability
- Room temperature: 72 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 this test?
The 12-hour urine calcium test measures how much calcium is excreted in your urine over a 12-hour period. Calcium is an essential mineral that plays important roles in bone health, muscle function, nerve signaling, and blood clotting. This test helps your healthcare provider understand how your body processes calcium and how well your kidneys are working.
Why do I need this test?
Your doctor may order this test if you have symptoms or conditions related to abnormal calcium levels, such as kidney stones, bone pain, weakness, fatigue, or irregular heart rhythms. It is also used to monitor conditions affecting the parathyroid glands, evaluate kidney function, and assess certain metabolic disorders.
How do I prepare for the test?
Your healthcare provider may ask you to follow specific instructions before the test. You may need to maintain your normal diet for 24 hours before and during the collection period. Certain medications, such as diuretics, antacids, or vitamin D supplements, may affect results. Inform your doctor about all medications and supplements you are taking. Avoid strenuous exercise during the collection period, as it can affect calcium levels.
How is the test performed?
You will receive a special container for urine collection. On the morning of the test, urinate and discard that first sample. Note the exact time. For the next 12 hours, collect all urine in the container. At the end of 12 hours, urinate one final time and add that sample to the container. Keep the container refrigerated or in a cool place during collection. Return the container to your healthcare provider or laboratory as instructed.
What do the results mean?
Normal urine calcium levels vary depending on diet and laboratory methods. High urine calcium (hypercalciuria) may indicate kidney stones, hyperparathyroidism, certain cancers, or excessive vitamin D intake. Low urine calcium (hypocalciuria) may indicate hypoparathyroidism, vitamin D deficiency, kidney disease, or malabsorption problems. Your doctor will interpret your results based on your symptoms, medical history, and other test results.
Are there any risks?
There are no significant risks associated with this test. The main challenge is collecting all urine samples accurately during the 12-hour period. Missing any sample may require repeating the test.
Reference range
No established fixed range (varies widely with hydration/diet; often ~0.5-40 mg/dL approximate for concentration)not specified
Complete accurate 12-hour urine collection; no fasting required. Acid preservative may be needed; maintain usual diet unless otherwise directed.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Can I collect urine at home for this test?
Does diet affect urine calcium levels?
What happens if I miss a urine sample during collection?
Do I need to fast before this test?
How long does it take to get results?
Can medications affect the test 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