The color of urine is like black tea, or red, white, or green. What’s going on?

Author: Zhang Yong, Chief Physician, Beijing Tiantan Hospital, Capital Medical University

Reviewer: Zhang Kai, Chief Physician, Peking University First Hospital

Under normal circumstances, people urinate every day, and more than once. Four or five times, five or six times, or seven or eight times are normal.

We can directly observe changes in urine. Normal urine should be clear and transparent with a slightly yellowish color. If the urine color is abnormal, such as red, green, or white, it may indicate different diseases. Please seek medical attention in time.

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1. Why is my urine the same color as black tea?

Dark brown urine, like black tea, may be caused by the following reasons.

First, drinking less water results in less urine and concentrated urine, which can lead to redness and yellowing.

Second, there are red blood cells in the urine, which is hematuria;

Third, with bile duct disease, bilirubin is excreted in the urine, making the urine red in color.

2. Why is urine red?

If the urine is red, first rule out whether you have eaten any food. For example, the most common food is pitaya. Eating red pitaya may cause the urine to turn red. There is also beet. After frying beet, the soup is red, and eating it will also cause the urine to turn red.

After stopping the intake of these foods, check whether the urine returns to normal after a day. If the urine is still red, it may be gross hematuria caused by disease, such as urinary tract infection, urinary tract stones, urinary tract tumors, etc.

3. Why does urine turn white or green?

If the urine is whitish and mixed with some flocculent sediment, it often indicates that it is caused by a urinary tract infection. A large number of white blood cells are excreted in the urine. The white blood cells clump together and float in the urine like clouds, which is called pyuria.

If the urine is milky white, it may be chyluria, which is urine mixed with lymph fluid containing chylomicrons, causing the color of the urine to change.

If the urine is grayish white, there may be some inorganic salts or stone components excreted in the urine, which is often related to urinary stones.

Green urine is rare, and most of the time it is related to medication or food. For example, methylene blue is often used for development in medical examinations. When the drug is excreted from the urine, it can turn the urine green. In addition to medication and food, some green urine is related to diseases and requires further examination.

In addition to changes in urine color, sometimes you will find that the urine is particularly turbid and has a strong smell. What is going on?

4. Why does urine have a strong odor and is turbid?

If your urine has a strong odor, it may be related to the food you eat, such as onions and garlic. If you eat more of them, the smell of your urine may change.

If the urine of a diabetic patient is left for a long time, it will have a smell like rotten apples after the sugar in the urine ferments.

If you do not urinate for a long time, your urine will be turbid. If you leave it for a long time, it will have a stronger smell of ammonia.

The most common cause of cloudy urine is infection, including kidney infection, bladder infection, urinary tract infection, etc., which may cause cloudy urine.

If there is any abnormality in the urine, whether it is a change in color, odor, or properties, if you cannot see a doctor immediately, you can observe for a day or two to see if it can return to normal, such as by drinking water or adjusting your diet. If not, you should seek medical attention promptly.

The easiest way to identify the cause of urine changes is to do a routine urine test to see if there are red blood cells in the urine, the number of red blood cells, white blood cells, and urine sugar, etc. If the urine routine test confirms hematuria or infection, further tests such as ultrasound, CT, and even MRI are required to find the cause and site of bleeding, and then give appropriate treatment after the cause and site are identified.

In addition, you need to pay attention to the following matters when doing a routine urine test to ensure the accuracy of the test results so as not to affect the diagnosis of the disease.

5. What should you pay attention to when doing a routine urine test?

Generally speaking, you need to keep fresh, clean, midstream urine.

Fresh urine means it is best to urinate on the spot in the hospital and then have it checked.

Can I bring my morning urine from home? In principle, urine within two hours can be tested, but urine within half an hour will give the most accurate test results.

Clean urine. It is best to clean the local area when retaining urine. Men need to lift up the foreskin and clean the glans penis; women should clean the vulva and separate the labia to clean. This can eliminate false positives caused by local uncleanliness.

Midstream urine refers to the urine at the beginning of urination (5-10ml), which should be kept, and the urine at the end of urination (2-3ml), and the urine in the middle should be kept.

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You can collect urine at any time for a routine urine test, but it is best to collect urine during normal life.

For example, if you drink three glasses of water every day, it is close to normal to have your urine checked in this state. If you don't drink so much water on a normal day, but drink a lot of water for the test, the osmotic pressure of the urine will decrease, the solute will decrease, and the white blood cells and red blood cells in the urine will lyse in the hypotonic state, which can easily cause a false negative, that is, the test is fine, but in fact there is a problem.