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12-Hour Urinary Calcium Excretion Rate

Published: August 9, 2026Updated: August 16, 2026

This test measures how much calcium your kidneys filter and excrete into your urine over a 12-hour period. It helps assess kidney function and calcium balance in your body.

Quick summary

["A 12-hour urine calcium test helps diagnose kidney issues or calcium-related disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
57339-4
Short code
Citrate 12h Ur-mRate
Synonyms
Citrate 12h Ur-mRate
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you have symptoms like kidney stones, unexplained bone pain, or signs of kidney problems. It can also be used to monitor conditions like hypercalcemia (high calcium levels) or hyperparathyroidism.

How the Test Works

You’ll collect urine for 12 hours, typically starting after an overnight fast. The sample is analyzed to determine the amount of calcium passed in urine, which helps evaluate kidney function and calcium metabolism.

Sample Collection Process

You’ll need to collect all urine for a full 12-hour period, often starting after waking up. Use a clean container and record the time each urine sample is voided. Avoid foods high in calcium (like dairy) if instructed by your doctor.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications or foods that could affect results. Follow your doctor’s instructions carefully.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

High urinary calcium excretion may indicate kidney stones, overactive parathyroid glands, or other metabolic disorders. Low excretion could suggest kidney disease or malabsorption issues. Results help guide treatment for conditions like osteoporosis or hypercalcemia.

Short name

12-hour urine calcium

Frequently asked questions

What does a high urinary calcium level mean?
A high urinary calcium level may suggest conditions like kidney stones, hyperparathyroidism, or excessive calcium intake. Your doctor will review your symptoms and other test results to determine the cause.
What does a low urinary calcium level mean?
A low urinary calcium level may indicate kidney problems, malabsorption syndromes, or certain medications that reduce calcium excretion. Further testing will help identify the underlying issue.
Can diet affect this test?
Yes, diet can influence urinary calcium levels. High intake of calcium-rich foods or supplements may temporarily increase excretion. Follow your doctor’s advice on dietary restrictions if applicable.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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