24-Hour Urine Collection

24-Hour Urine Collection

(24-hour urine, urine volume)

Procedure overview

What is a 24-hour urine collection?

Illustration of the anatomy of the kidney
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A 24-hour urine collection is a simple diagnostic procedure that measures the components of urine. The test is noninvasive (the skin is not pierced), and is used to assess kidney (renal) function.

Twenty-four hour urine collection is performed by collecting a person's urine in a special container over a 24-hour period. The container must be kept cool during this time until it is returned to the lab for analysis.

Urine consists of water and dissolved chemicals such as sodium, potassium, urea (formed from protein breakdown), and creatinine (formed from muscle breakdown), along with other chemical compounds. Normally, urine contains specific amounts of these waste products. If these amounts are not within a normal range, or if other substances are present, it may be an indication of a particular disease or condition. The results of a 24-hour urine collection may provide information to help your doctor make or confirm a diagnosis.

Related procedures that may be used to diagnose kidney disease include kidney ultrasound, kidney scan, kidney biopsy, and renal arteriogram.

How does the urinary system work?

Illustration of the anatomy of the urinary system, front view
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The body takes nutrients from food and converts them to energy. After the body has taken the nutrients it needs from the food, waste products are left behind in the bowel and blood.

The urinary system keeps chemicals, such as potassium, sodium, and water in balance, allowing the body to function properly. The kidneys also remove protein waste, called urea, from the blood. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys.

Other important functions of the kidneys include blood pressure regulation, and the production of erythropoietin, which controls red blood cell development in the bone marrow.

Urinary system parts and their functions:

Facts about urine:

Reasons for the procedure

Twenty-four hour urine collection is a quick, simple diagnostic test that helps to diagnose problems with the kidneys. It is commonly performed to determine how much creatinine clears through the kidneys, but may also be used to measure protein, hormones, minerals, and other chemical compounds. Creatinine clearance testing provides information about kidney function.

Like all organs in the human body, the kidneys may be affected by various genetic and environmental circumstances, leading to kidney disease. Kidney (renal) disease may be temporarily or permanently damaging. Acute kidney disease has an abrupt onset and is potentially reversible. Chronic kidney disease progresses slowly over at least three months and can lead to permanent kidney damage. The causes, symptoms, treatments, and outcomes of acute and chronic kidney disease are different.

Conditions that can cause kidney disease include, but are not limited to, the following:

Twenty-four hour urine collection may be performed along with other diagnostic procedures, such as cystometry and cystography.

There may be other reasons for your doctor to recommend 24-hour urine collection.

Risks of the procedure

Twenty-four hour urine collection is a safe, noninvasive procedure that is usually done without direct assistance.

Certain factors or conditions may interfere with the accuracy of a 24-hour urine collection. These factors include, but are not limited to, the following:

There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure. 

Before the procedure

During the procedure

Twenty-four hour urine collection may be performed on an outpatient basis or as part of your stay in the hospital. Procedures may vary depending on your condition and your doctor's practices.

Generally, 24-hour urine collection follows this process:

  1. You will be given one or more containers for collecting and storing your urine. A brown plastic container is typically used to store the urine. A specimen pan or urinal may be used to collect the urine. You will need to transfer the urine from the collecting container to the storage container where it will be kept cold.
  2. The 24-hour collection may begin at any time during the day after you urinate.  However, it is common to start the collection the first thing in the morning. It is important to collect all urine in the following 24-hour period.
  3. Do not save the urine from your first time urinating--the starting time. Flush this first specimen, but note the time. This will be the start time of the 24-hour collection.
  4. All urine, after the first (flushed) specimen, will be saved, stored, and kept cold, either on ice or in a refrigerator, for the next 24 hours.
  5. Try to urinate again at the same time, 24 hours after the start time, to finish the collection process, but if you cannot urinate at this time, it is not a problem.
  6. Once the urine collection has been completed, the urine containers will be taken to the lab. If you are doing the urine collection at home, you will be given instructions on how and where to transport the specimen.
  7. The procedure is concluded at this point. Depending on your specific medical condition, you may be asked to perform the test on several consecutive days.

After the procedure

Generally, there is no special type of care following 24-hour urine collection. However, your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.

Online resources

The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your doctor. Please consult your health care provider with any questions or concerns you may have regarding your condition.

This page contains links to other websites with information about this procedure and related health conditions. We hope you find these sites helpful, but please remember we do not control or endorse the information presented on these websites, nor do these sites endorse the information contained here.

American Urological Association

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

National Institutes of Health (NIH)

National Kidney Foundation

National Library of Medicine

 

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