What is a 24-hour urine collection?
A 24-hour urine collection is a simple lab test that measures what’s in your urine. The test is used to check kidney function. A 24-hour urine collection is done by collecting your urine in a special container(s) over a full 24-hour period. The container(s) must be kept cool until the urine is returned to the lab.
Urine is made up of water and dissolved chemicals, such as sodium and potassium. It also contains urea, which is made when protein breaks down, and creatinine, which is formed from muscle breakdown. 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 a sign of a certain disease or condition.
Why might I need a 24-hour urine collection?
Twenty-four hour urine collection helps diagnose kidney problems. It is often done to see how much creatinine clears through the kidneys. It’s also done to measure protein, hormones, minerals, and other chemical compounds.
Conditions that can cause kidney disease include:
Diabetic nephropathy. This is a result of uncontrolled diabetes. It causes high levels of protein (albumin) in the urine and can lead to kidney damage.
High blood pressure. Abnormally high blood pressure can lead to permanent kidney damage.
Lupus nephritis. Inflammation of the kidneys can be caused by lupus, an autoimmune disease where the immune system attacks the kidneys and damages them.
Frequent urinary tract infections.
Prolonged urinary tract blockage.
Alport syndrome. This inherited health problem causes vision and hearing problems, as well as progressive scarring of the kidneys.
Nephrotic syndrome. This condition that has several different causes. It is characterized by protein in the urine, low protein in the blood, high cholesterol levels, and tissue swelling.
Polycystic kidney disease. This genetic disorder is characterized by the growth of many fluid-filled cysts in the kidneys. This makes the kidneys larger and, over time, takes over and destroys working kidney tissue.
Interstitial nephritis or pyelonephritis. This is an inflammation in the small structures in the kidney. It’s often caused by infection.
Screening for preeclampsia in pregnancy. Preeclampsia is a dangerous health problem that sometimes occurs in pregnancy. It’s associated with blood pressure and organ failure.
There may be other reasons for your health care provider to recommend 24-hour urine collection.
What are the risks of a 24-hour urine collection?
Twenty-four hour urine collection is a safe, easy test. People can collect urine on their own.
Certain factors or conditions may interfere with the accuracy of a 24-hour urine collection. These factors include:
- Forgetting to collect some of your urine
- Going beyond the 24-hour collection period and collecting too much urine
- Losing urine from the specimen container through spilling
- Not keeping urine cold while collecting it
- Acute stress
- Vigorous exercise
- Certain foods, such as coffee, tea, cocoa, bananas, citrus fruits, vanilla, can change urine test results
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your health care provider before the procedure.
How do I get ready for a 24-hour urine collection?
- Your health care provider will explain the procedure and you can ask questions.
- Make sure you understand if you need to avoid certain foods while collecting your urine.
- No other preparation is needed.
- You will be given large containers to store your urine and a container to urinate into. Make sure you know how to use them and have a cold place to store the urine while you’re collecting it. For instance, a refrigerator or in a cooler on ice.
- You may be instructed to start the collection at a specific time.
- If possible, choose a 24-hour period when you will be at home so you do not have to transport your urine.
- If you are pregnant or think you may be, tell your health care provider.
- Make sure your health care provider has a list of all medicines (prescription and over-the-counter), herbs, vitamins, and supplements that you are taking.
Based on your medical condition, your health care provider may request other specific preparation.
What happens during a 24-hour urine collection?
A 24-hour urine collection may be done on an outpatient basis or during a hospital stay. Procedures may vary depending on your condition and your health care provider's practices.
Generally, a 24-hour urine collection follows this process:
- You will be given one or more containers for collecting and storing your urine. A brown plastic container is typically used. A specimen pan that fits in the toilet or a urinal may be used to collect the urine. You will need to transfer the urine from the collecting container to the storage container, and will need to keep it cold.
- The 24-hour collection may start at any time during the day after you urinate, but your health care provider may tell you when to start. 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.
- Do not save the urine from your first time urinating--the starting time. Flush this first specimen, but note the time. This is the start time of the 24-hour collection.
- All urine, after the first (flushed) specimen, must be saved, stored, and kept cold, either on ice or in a refrigerator, for the next 24 hours.
- 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.
- Once the urine collection has been completed, the urine containers will need to be taken to the lab as soon as possible. If you are doing the urine collection at home, you will be given instructions on how and where to take it.
- Depending on your specific medical condition, you may be asked to repeat the collection over several days.
What happens after a 24-hour urine collection?There is no special type of care after a 24-hour urine collection. However, your health care provider may give you other instructions after the procedure, depending on your particular situation.
Next stepsBefore you agree to the test or the procedure make sure you know:
- The name of the test or procedure
- The reason you are having the test or procedure
- The risks and benefits of the test or procedure
- When and where you are to have the test or procedure and who will do it
- When and how will you get the results
- How much will you have to pay for the test or procedure