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24-Hour Urine Collection
A 24-hour urine collection gathers all the urine you pass over a full day to measure substances such as protein, hormones or minerals accurately.
Quick answer
24-Hour Urine Collection: what it is and what the results mean
A 24-hour urine collection involves saving every drop of urine you produce over a full 24-hour period in a special container. Measuring the total amount of a substance over a day gives a more accurate result than a single sample.
- Why it is done: It is used to measure protein loss, kidney function (creatinine clearance), certain hormones, minerals and stones-related chemicals, and to investigate conditions of the kidneys, adrenal glands and metabolism.
- Understanding results: The laboratory measures the total amount of the substance over the day.
What it is
A 24-hour urine collection involves saving every drop of urine you produce over a full 24-hour period in a special container. Measuring the total amount of a substance over a day gives a more accurate result than a single sample.
Why it is done
It is used to measure protein loss, kidney function (creatinine clearance), certain hormones, minerals and stones-related chemicals, and to investigate conditions of the kidneys, adrenal glands and metabolism.
What to expect
You are given a large container, sometimes with a preservative. You start by emptying your bladder and discarding that urine, then collect all urine for the next 24 hours, including the final sample, and keep it cool.
Understanding the results
The laboratory measures the total amount of the substance over the day. Results are interpreted against normal ranges to diagnose or monitor conditions such as kidney disease, hormone disorders or recurrent kidney stones.
Good to know
Risks and limitations
It is completely safe but relies on collecting every sample — missing any urine makes the result inaccurate. Some containers hold preservatives that need careful handling.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
24-Hour Urine Collection: frequently asked questions
What happens if I miss collecting some urine?
Missing even one sample makes the total inaccurate, which could give a misleading result. If you miss a collection, it is usually best to restart the 24 hours; ask the laboratory for advice.
Do I include the first urine of the day?
No. You empty your bladder at the start and discard that urine, then collect everything for the next 24 hours, finishing with a sample at the exact end time.
Related tests
Other other investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Association for Laboratory Medicine / relevant professional body
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