A 24-hour urine test is requested so that kidney function can be evaluated, which is very useful for identifying and monitoring kidney disease.
This test is indicated primarily to measure kidney function or to assess the amount of protein or other substances in your urine, such as sodium, calcium, oxalate, or uric acid, for example and also to identify kidney and urinary tract diseases.
To do this test, it is necessary to collect all the urine in a container given by the laboratory during a period of 24 hours, and then the container must be taken to the laboratory that will analyze the values. Learn more about other urine tests that exist and how to collect the urine.
What is the purpose of a 24 hour urine test
The 24-hour urine test is used to evaluate kidney function to detect possible kidney changes by determining the amount of some substances in the urine such as:
- Creatinine clearance evaluating the rate of kidney filtration;
- Proteins, including Albumin;
- Uric acid;
Other substances such as ammonia, urea, magnesium and phosphate can also be quantified in this test.
In this way, a 24-hour urine can help your doctor identify problems such as kidney failure, kidney tubule disease, causes of stones in your urinary tract, or nephritis, which is a set of diseases that cause inflammation of the kidney glomeruli.
In pregnancy, this test is usually used to determine the presence of proteins in the pregnant woman's urine for the diagnosis of pre-eclampsia, which is a complication that arises during pregnancy, in which the pregnant woman develops hypertension, fluid retention and protein loss through urine.
How to collect urine for the test
To do a 24 hour urine test, you should follow the steps below:
- Get a proper container from the laboratory;
- The next day, early in the morning, just after waking, you should urinate, but not put the first jet of urine in the container;
- Write down the exact time you urinated each time;
- After you have urinating the first time, collect all the urine of the day and night in the container;
- The last urine to be collected in the container should be at the same time of the previous day's first urine with a tolerance of 10 minutes.
For example, if you urinated at 8 o'clock one day, the urine collection should end at exactly 8 o'clock the next day or at least 7:50 am and at most 8:10 am.
Cautions during urine collection
During the collection of 24-hour urine, it is necessary to have certain cautions such as:
- If you are to evacuate, you should not urinate in the toilet because all the urine should be placed in the container;
- If you go for a shower, you can not urinate in the bath;
- If you leave home, you must carry the container with you or you can not urinate until you return home;
- You can not do the 24 hour urine test if you are having your period.
Between urine collections, the container should be in a cool, preferably refrigerated, place. When the collection is complete, the container should be taken to the laboratory as soon as possible.
Some of the reference values for a 24-hour urine test are:
Clearance of creatinine between 80 and 120 ml / min, which may be decreased in kidney failure;
- Albumin: less than 30 mg / 24 hours;
- Total proteins: less than 150 mg / 24 hours;
- Calcium: no diet until 280 mg / 24 h and with diet 60 to 180 mg / 24 h.
These values may vary according to your age, sex, health conditions and the laboratory that is analyzing the test, so you should always be evaluated by a doctor, who will indicate the need for treatment.
The 24-hour urine test due to the difficulty in collecting and frequent errors that may occur has been less and less requested in medical practice and replaced by other more recent tests such as mathematical formulas that can be made after a simple urinalysis.