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Calcium24hurmrate

Published: July 31, 2026Updated: August 16, 2026

A test that measures the amount of calcium in your urine collected over 24 hours to evaluate calcium metabolism and kidney stone risk.

Quick summary

{"This test measures how much calcium your kidneys excrete in a 24-hour period","It helps diagnose conditions like kidney stones, hyperparathyroidism, and bone diseases","You will need to collect all your urine in a special container for 24 hours","Certain medications and diet can affect your test results","Results are expressed as milligrams of calcium per 24 hours (mg/24h)"}

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

Key facts at a glance

LOINC
6874-2
Short code
CAU24
Synonyms
Calcium 24h Ur-mRate
Category
electrolyte
Sample
urine
Container
24-hour urine collection container (acid-washed or plain plastic container)
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
0–120 years
Method
Colorimetric (Arsenazo III or o-cresolphthalein complexone)
CPT
82340
SNOMED
365761006
Specimen volume
Complete 24-hour collection, typically 1000-2000 mL
Stability
Refrigerated: 7 days; Room temperature: 48 hours; 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 24-hour urine calcium test measures the total amount of calcium that your kidneys eliminate in your urine over a 24-hour period. Calcium is an important mineral that plays a key role in bone health, muscle function, nerve transmission, and blood clotting. Your body carefully regulates calcium levels through hormones like parathyroid hormone (PTH) and vitamin D.

Why is it performed?

Your healthcare provider may order this test to: evaluate recurrent kidney stones, assess parathyroid gland function, diagnose bone diseases such as osteoporosis or osteomalacia, monitor conditions that affect calcium metabolism, and evaluate certain cancers that may affect calcium levels.

How to prepare and collect the sample

Before the test, inform your doctor about all medications you take, as some medicines can affect results. You may be asked to avoid certain supplements or adjust your diet for 24-48 hours before and during collection. On the morning of the test, start by urinating into the toilet and note the exact time. For the next 24 hours, collect all urine in the provided container. Keep the container refrigerated or in a cool place. At the exact same time the next morning, urinate into the container one last time to complete the collection.

Understanding your results

Normal urine calcium levels typically range from 100 to 300 mg per 24 hours. However, reference ranges may vary by laboratory. Your doctor will interpret your results based on your overall health, diet, and other test results. A single abnormal result does not necessarily indicate a problem—your provider may order repeat testing or additional tests to confirm findings.

Reference range

100-300 mg/24 hnot specified

Specimen: urine

Collect entire 24-hour urine output into provided container (often with acid preservative); maintain usual diet and fluid intake unless otherwise instructed; discard first morning void and collect all subsequent urine including next morning void

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings2

Frequently asked questions

Does the 24-hour urine collection have to be exactly 24 hours?
Yes, accuracy depends on exactly 24 hours. Start in the morning after your first urine, and end at the same time the next day. Try to collect at the exact same times to ensure accurate results.
Can I exercise during the collection period?
Avoid strenuous exercise during the 24-hour collection, as intense physical activity can affect calcium levels in urine. Light activities are generally acceptable.
What if I forget to collect a urine sample?
If you miss a sample, note the time and continue collecting. Tell your healthcare provider about any missed collections, as they may need to repeat the test for accurate results.
Do I need to follow a special diet before the test?
Your doctor may ask you to maintain your normal diet for accurate results. However, you should avoid calcium supplements for 24-48 hours before the test unless directed otherwise. Follow any specific instructions given by your healthcare provider.
Is the 24-hour urine calcium test safe?
Yes, this is a simple, non-invasive test. The only risk is possibly needing to urinate more frequently while increasing fluid intake, which is often recommended to help flush the kidneys.
  1. 1
    MedlinePlus - Urine Calcium LevelSource
  2. 2
    Mayo Clinic - Urine TestSource
  3. 3
    National Kidney Foundation - Kidney StonesSource

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