Can I drink water before a urine test? What are the effects?

Urinalysis is a very simple medical test item. Generally, the morning urine of the subject is used for examination. If there is no specific requirement for morning urine, the middle section of urine should also be taken for examination. One thing you need to pay attention to when doing a routine urine test is whether you can drink water before the test. This depends on the purpose of the test.

Generally, there will be no impact if you do a urine test after a meal or after drinking water. However, if you drink a lot of water, it will affect the urine specific gravity. This result indicates that urine occult blood is weakly positive. If you are a female, it is recommended to avoid the menstrual period and have another check-up. If you are a male, it is recommended to do another urine routine check. If it is normal, then there is nothing wrong. If it is abnormal, it is recommended to do a kidney B-ultrasound examination.

When unexplained edema, low back pain, frequent urination, urgency, etc. occur, doctors often ask patients to do a routine urine test and ask patients to frequently review the results of routine urine tests. Routine urine tests can be carried out in laboratories at all levels of hospitals and are the simplest, most painless and rapid means of examination. The purpose of a routine urine test is to understand the general condition of the kidneys and whether there are any lesions. It can also be used to understand whether lesions in other organs have caused damage to kidney function, or to understand whether drug treatment has an effect on the kidneys and observe the effect of treatment.

A routine urine examination generally includes three items: urine protein qualitative examination, urine sugar qualitative examination and urine sediment examination. Nowadays, since many hospitals use semi-automatic or automatic urine analyzers, routine urine test results can provide 8 to 10 measurement data at the same time. These data generally include urine protein, urine sugar, urine ketone bodies, urine specific gravity, pH, urine bilirubin, urobilinogen, nitrite, red blood cells (occult blood) and white blood cells. Some instruments also include qualitative tests for interference with urinary elimination of vitamins.

Can I drink water before a urine test?

If you drink an appropriate amount of water before the urine test, it will not affect the test results, because the current routine urine test includes chemical analysis and formed component examination. Under normal circumstances, a person's urine volume is within a certain range, and the normal reference value of the test results is obtained by statistics based on the normal water intake of ordinary people. However, if you drink a lot of water beyond the normal limit, it will lead to increased glomerular filtration and excessive urine output. If the urine sugar is abnormal, often +~±, then the result may be negative after drinking a lot of water, thus resulting in a false negative.

Don't drink a lot of water before taking a urine test

Urinalysis mainly checks the formed elements in urine, such as cells, casts, crystals, etc. Drinking a lot of water will dilute the urine, resulting in a decrease in urine specific gravity, which is an important indicator for estimating the kidney's concentrating function. In addition to not drinking water, you should also not drink beverages or eat fruits. However, the detection of protein, occult blood and other items in urine tests are basically not affected by drinking water.