24-hour urine phosphorus test
Quick answer: This test measures how much phosphorus your kidneys pass into urine over 24 hours. It is usually ordered with calcium tests to look into kidney stones, bone disease or parathyroid and kidney problems.
- Sample24-hour urine
- Takes24 hours of collection at home
- Before the testCollect all your urine for 24 hours in the container provided, following the lab's instructions.
How the test is done
- 1You get a clean container from the lab with written collection steps
- 2You flush the first morning urine and write down the time
- 3You collect all urine for the next 24 hours, keeping the container cool
- 4You add the next morning's first urine and return the container
What your results can mean
Reading your report
Normal ranges differ between labs and by age and sex, so discuss your result with your doctor.
If the result is outside the usual range
A high level can be seen with an overactive parathyroid gland, some kidney tubule problems or a high-phosphate diet. A low level can be seen with low vitamin D, poor intake or some kidney problems.
Who usually has this test
People being checked for kidney stones, bone disease or abnormal blood phosphate.
Risks and aftercare
There are no physical risks; the main challenge is remembering to collect every sample.
Names and options
Also called: urine phosphate 24 hour
Listed by the hospital as
- 24 HR URINE PHOSPHORUS
Questions about this test
Why is urine phosphorus often tested with calcium?
Calcium and phosphate are handled together by the kidneys, bones and parathyroid glands. Looking at both helps your doctor understand stone risk and bone problems.
Does food affect a 24-hour urine phosphorus result?
Yes. Protein-rich foods, dairy and fizzy drinks contain phosphate, so intake affects how much you pass. Most doctors ask you to eat as usual so the result reflects your normal diet.
How do I keep the urine container cool?
Keep it in a cool, shaded place or in a bag with ice packs, as the lab advises. Do not freeze it unless told to.
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Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
Get directions ↗IVF Pulse fertility care at Tamara Hospital →
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.