Calcium12hurmrate
A test that measures the amount of calcium in your urine collected over 12 hours to evaluate calcium metabolism and kidney function.
{"This test measures calcium excreted in urine over 12 hours","It helps diagnose conditions like kidney stones, bone disorders, and parathyroid problems","You will collect all urine in a special container for 12 hours","Results show if your body is excreting too much or too little calcium","Abnormal results may indicate kidney disease or metabolic disorders"}
Key facts at a glance
- LOINC
- 18186-7
- Short code
- CA U12H
- Synonyms
- Calcium 12h Ur-mRate
- Category
- electrolyte
- Sample
- urine
- Container
- Clean, labeled plastic urine container (preferably amber or dark container to protect from light)
- 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
- 0–120 years
- Method
- Atomic absorption spectrometry (AAS) or colorimetric method (arsenazo III dye binding)
- CPT
- 82340
- SNOMED
- 271567001
- Specimen volume
- 10-20 mL from well-mixed 12-hour collection
- 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 this test?
The 12-hour urine calcium test measures how much calcium your kidneys excrete in your urine over a 12-hour period. Calcium is an essential mineral important for bone health, muscle function, and nerve signaling. Normally, your kidneys filter calcium from the blood, and most of it is reabsorbed back into the body. This test helps doctors understand if your kidneys are handling calcium properly or if there are abnormalities in calcium metabolism.
How is the test performed?
You will receive a special container from your healthcare provider. On the day of the test, you will begin collecting your urine at a specific time (usually in the morning) and continue collecting every urine sample for the next 12 hours. It is important to collect all urine during this period, including the first morning urine on the second day. Keep the container refrigerated or on ice during the collection period. Once complete, return the container to your lab or healthcare provider as instructed.
Why might 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 frequent urination. It is also used to monitor patients with known kidney disease, parathyroid disorders, or certain bone diseases. Additionally, this test can help evaluate the effectiveness of treatments for calcium-related conditions.
What do the results mean?
High urine calcium levels (hypercalciuria) may indicate conditions such as kidney stones, hyperparathyroidism, certain cancers, osteoporosis, or excessive vitamin D intake. Low urine calcium levels (hypocalciuria) may be seen in hypoparathyroidism, vitamin D deficiency, kidney failure, or certain medications. Your doctor will interpret your results based on your overall health, symptoms, and other test results.
Are there any risks or preparations?
There are no significant risks associated with this test. However, your doctor may ask you to avoid certain foods, vitamins, or medications for 24 hours before and during collection, as these can affect results. It is important to stay well-hydrated during the collection period unless otherwise instructed. Follow all specific instructions provided by your healthcare team carefully to ensure accurate results.
Reference range
50-150 mg/12 hnot specified
Exact 12-hour timed urine collection required (empty bladder at start, collect all urine including final void); refrigerate specimen during collection; note dietary calcium intake
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Do I need to fast before the test?
What happens if I miss collecting some urine during the 12-hour period?
Can I exercise during the collection period?
How long does it take to get results?
What happens if my results are abnormal?
Can I take my regular medications during the test?
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