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Serum Calcium with 24-Hour Urinary Excretion Rate (Calcium Clearance)

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

This test measures how well your kidneys filter calcium from your blood and excrete it in urine over a 24-hour period.

Quick summary

["Assesses kidney function and calcium balance in your body."]

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

Key facts at a glance

LOINC
24535-7
Short code
XR Acetabulum Views
Synonyms
XR Acetabulum Views
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you have symptoms like kidney stones, bone pain, or signs of abnormal calcium levels. It helps evaluate how well your kidneys are managing calcium metabolism, especially if you have conditions like chronic kidney disease or hypercalcemia.

How the Test Works

You’ll collect a 24-hour urine sample (starting and ending at the same time) and provide a blood sample. Calcium levels in both are measured to calculate your clearance rate, which reflects kidney function in filtering calcium.

Preparation

Follow your doctor’s instructions carefully. Drink plenty of water to help flush calcium from your system. Avoid certain medications (like calcium supplements or diuretics) that may affect results.

What to Expect

The urine collection requires timing—you’ll need to measure urine output every hour for 24 hours. Blood is drawn in a clinic or lab. Results take a few days to process.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low clearance may indicate kidney problems or excessive calcium retention, while high clearance could suggest underactive kidneys or other metabolic disorders. It helps diagnose conditions like hypercalciuria (excess calcium in urine) or kidney stones.

Short name

Calcium Clearance (24h)

Frequently asked questions

What causes abnormal results?
Abnormal results may be linked to kidney disease, bone disorders (like osteoporosis), certain medications, or metabolic conditions. Your doctor will review your full medical history and other test results to interpret the findings.
How long does it take to get results?
Results typically take 3–7 business days, depending on lab processing times. Your doctor will contact you once they’re ready for discussion.
Can I eat or drink anything before the test?
No special diet is needed for the blood draw, but for the urine collection, follow your doctor’s instructions precisely—avoid foods high in calcium (like dairy) if specified.
  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