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Calcium2hurmrate

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

A urine test that measures the amount of calcium excreted in urine over a 2-hour period to evaluate calcium metabolism and kidney function.

Quick summary

{"Measures calcium levels in urine collected over 2 hours","Helps diagnose conditions like kidney stones and hypercalciuria","Used to monitor parathyroid and bone disorders","Requires a specific 2-hour urine collection procedure","Results help doctors assess calcium balance in your body"}

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

Key facts at a glance

LOINC
16518-3
Short code
CA2HRU
Synonyms
Calcium 2h Ur-mRate
Category
electrolyte
Sample
urine
Container
Sterile plastic urine container (no preservatives)
Units
not specified
Ref low
8
Ref high
25
Critical range
50 not specified – 400 not specified
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
Atomic absorption spectrometry (AAS) or Colorimetric (Arsenazo III)
CPT
82340
SNOMED
271571006
Specimen volume
Minimum 10 mL, typically entire 2-hour collection volume (varies 50-500 mL depending on urine output)
Stability
Refrigerated: 7 days; Room temperature: 24-48 hours; For longer storage, freeze at -20°C
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
24–72 hours
Order
routine

What is this test?

The 2-Hour Urine Calcium test measures the amount of calcium your kidneys excrete in urine over a 2-hour period. Calcium is an essential mineral for strong bones, muscle function, nerve signaling, and blood clotting. This test helps doctors understand how your body processes calcium and whether your kidneys are properly regulating calcium levels.

During the test, you will collect all urine produced during a 2-hour period into a special container provided by your healthcare provider. The sample is then sent to a laboratory where technicians measure the calcium concentration using specialized equipment.

Why is this test performed?

Your doctor may order this test if you have symptoms or conditions related to abnormal calcium metabolism, such as kidney stones, bone pain, weakness, fatigue, or frequent urination. It is also used to monitor patients with parathyroid disorders, vitamin D deficiency, or those taking medications that affect calcium levels.

How to prepare for the test

Your doctor may provide specific instructions, but generally you should: continue your normal diet unless told otherwise, inform your doctor about all medications you take (especially diuretics, antacids, or vitamin D supplements), stay well-hydrated, and avoid strenuous exercise before the test. Women should inform their doctor if they are pregnant.

Understanding your results

Normal urine calcium levels typically range from 100 to 300 mg per 24 hours (or proportionally adjusted for the 2-hour collection). However, reference ranges may vary by laboratory. Your doctor will interpret your results based on your medical history, symptoms, and other test results.

Reference range

8-25 mg/2 hnot specified

Specimen: urine

Timed 2-hour collection after emptying bladder; normal diet unless otherwise instructed

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings2

Frequently asked questions

Is the 2-hour test better than a 24-hour urine test?
Both tests have different applications. The 2-hour test is convenient and provides a snapshot of calcium excretion, while the 24-hour test is more comprehensive and often considered the gold standard for evaluating total daily calcium excretion. Your doctor will choose the most appropriate test based on your clinical situation.
Does this test hurt?
No, this test only requires urine collection. There is no pain involved, though you may experience some discomfort from holding your bladder until the collection period begins.
What happens if I miss some urine during the collection?
It is important to collect all urine during the 2-hour period. If you miss any, tell your healthcare provider as they may need to restart the collection. Accurate collection is essential for reliable results.
Will I need to fast before this test?
Fasting is usually not required for a urine calcium test. However, follow any specific instructions provided by your doctor, as they may recommend avoiding certain foods or supplements before the test.
How long does it take to get results?
Results are typically available within 1-3 days, depending on the laboratory. Your healthcare provider will contact you with the results and explain what they mean for your health.
  1. 1
    MedlinePlus - Urine Calcium TestSource
  2. 2
    Mayo Clinic Laboratories - Urine CalciumSource
  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