The 24-hour urine test is an analysis of urine collected over 24 hours to evaluate kidney function, very useful for identifying and monitoring kidney diseases.
This test is mainly indicated to measure kidney function or evaluate the amount of proteins or other substances in the urine, such as sodium, calcium, oxalate or uric acid, for example, as a way to identify kidney and urinary tract diseases.
To carry out this test, it is necessary to collect all the urine in a specific container over a period of 24 hours, which must be taken to the laboratory that will analyze the values. Find out more about other urine tests that exist and how to collect them.
What is it for
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:
Other substances such as ammonia, urea, magnesium and phosphate can also be quantified in this exam.
In this way, 24-hour urine can help the doctor identify problems such as kidney failure, kidney tubule diseases, causes of urinary tract stones or nephritis, which is a set of diseases that cause inflammation of the kidney glomeruli. Understand better what nephritis is and what it can cause.
During 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 loss of proteins through the urine.
How to take the exam
To take the 24-hour urine test, you do not need to do any type of preparation, just follow the following steps:
- Search or container specific to the laboratory;
- The next day, first thing in the morning, after waking up, urinating in the toiletdisregarding the first urine of the day;
- Note the exact time of urination what he did in the toilet;
- After urinating in the toilet, collect all day and night urine in the container;
- A The last urine to be collected in the container must be at the same time as the previous day’s urine which he did in the toilet, with a tolerance of 10 minutes.
For example, if the person urinated at 8 am of the day, the urine collection must end exactly at 8 am of the following day or at least at 7:50 am and at the latest at 8:10 am.
Care during urine collection
During 24-hour urine collection, certain precautions must be taken, such as:
- If you are going to evacuate, you should not urinate in the toilet because all the urine must be placed in the container;
- If you are going to take a bath, you cannot urinate in the bath;
- If you leave the house, you have to take the container with you or you won’t be able to urinate until you return home;
- You cannot take a 24-hour urine test while menstruating.
Between urine collections, the container should be in a cool place, preferably refrigerated. When the collection is complete, the container must be taken to the laboratory as quickly as possible.
Reference values
Some of the reference values for the 24-hour urine test are:
- Creatinine clearance between 80 and 120 ml/min, which may be reduced in kidney failure. Understand what kidney failure is and how to treat it;
- Albumin: less than 30 mg/24 hours;
- Total proteins: less than 150 mg/ 24 hours;
- Calcium: without diet up to 280 mg/24h and with diet 60 to 180 mg/24h.
These values may vary depending on the person’s age, sex, health conditions and the laboratory that carries out the examination, so they should always be evaluated by the doctor, who will indicate the need for treatment.
The 24-hour urine test, due to the difficulty in collecting it and the frequent errors that can occur, has been less and less requested in medical practice, being replaced by other more recent tests, such as mathematical formulas that can be done after a simple urine test. .
