"Tea" was sent for testing pretending to be urine, and the result was "inflammation". Can routine urine tests really be trusted?

In 2007, a reporter pretended to be a patient and took the prepared "tea" to the hospital as a urine sample for examination. According to the urine routine test results, the reporter was diagnosed with "inflammation" and some doctors even prescribed anti-inflammatory drugs for him.

After the media reported the incident, 92 top-level hospitals across the country retested the tea, and 93.4% of the reports showed positive results, while only 6.6% showed negative results. The detection rate of white blood cells was 33.1%, and that of red blood cells was 22.0%. The Ministry of Health organized some major hospitals in Beijing to test the tea, and many of the test results also showed positive results. After that, some reporters used green tea as a substitute for urine again, and were all diagnosed with inflammation.

So, why does urine test frequently detect tea "inflammation"? Why does tea test result in positive occult blood? Where do white blood cells come from? Can urine test still accurately measure and detect kidney disease? Today's article will reveal the answers for you.

First of all, the positive result of tea water test for occult blood is mainly because the substances contained in the tea water react with the urine test strip, causing the color-developing substances to develop color. At this time, the urine analyzer mistakenly thinks that the occult blood is positive, causing the doctor to make a "positive" diagnosis. What needs to be told here is that the presence of occult blood in urine does not necessarily mean hematuria. This test method can only be used as a preliminary screening for hematuria, and further microscopic urine sediment examination must be performed.

Secondly, white blood cells are detected in tea mainly because tea contains a large number of unknown interfering substances. If "tea is used instead of urine", the phenols and other organic substances in the tea can be colored as long as they can react with the diazonium salt in the urine analysis test paper. The instrument will only judge whether white blood cells are contained based on the chemical reaction results. The current instrument does not have a procedure to identify whether the sample is urine. If the tea contains substances similar to those in urine, the instrument will automatically identify and generate results. In other words, occult blood and white blood cells may also be detected in soy sauce and beer.

Therefore, the detection of "cellular components" in tea was "caused by the machine" and was also a "misunderstanding" caused by the public's (including reporters) lack of understanding of common sense about urine tests.

How to avoid false positives?

At present, the standard detection method for red blood cells and white blood cells in urine is still manual microscopic examination of urine sediment. Therefore, it is required that urine processing should be standardized before urine sediment microscopic examination, and the inspection process should be completed by experienced inspection physicians in order to provide more accurate and comprehensive inspection results. If manual microscopic examination is used, cell components will definitely not be detected in tea.

Urine routine test precautions

Paying attention to the standard collection of urine specimens is the key to ensuring the accuracy of urine routine examination results. In order to improve the accuracy of urine routine examination and avoid the occurrence of false positive results, the following points should be noted when conducting urine routine examination:

01: During the urine routine test, the urine sample should be no less than 10 ml. 0 2: Generally, women are required to avoid menstruation when collecting urine samples to prevent vaginal secretions from mixing into the urine and affecting the test results. 0 3: Collect midstream urine, especially when doing urine routine and urine bacteriological tests. 0 4: Clean and dry containers should be used to collect urine, that is, disposable urine cups and urine test tubes provided by the hospital. 0 5: The urine should be sent to the laboratory for examination as soon as possible, because if it is too long, problems such as glucose being decomposed by bacteria, cast destruction, and cell lysis will occur, affecting the accuracy of the test results. In short, "tea inflammation" does not mean that there is a problem with the doctor's qualifications or medical equipment. The truth is that the urine analyzer itself cannot identify tea or other liquids other than human urine. It is a storm caused by the wrong use of the machine. Therefore, it is necessary for us to correctly understand the methods and significance of urine routine testing.