Small test, big effect - learn about urine routine!

Urinalysis is one of the must-check items in every physical examination. It is cheap, has no harm to the body, and will not cause any disease in the body, especially urinary system diseases. While monitoring whether drug treatment affects renal function and observing the effect of treatment, urinalysis can reflect the pathological conditions of the urinary system and multiple tissues and organs. At the same time, urine examination is a common clinical examination and diagnosis and treatment method that is easy to operate and affordable. It has important clinical significance for doctors to understand and judge the condition. Systemic diseases such as diabetes, blood diseases, hepatobiliary diseases, and epidemic hemorrhagic fever will also affect urine. Today, let’s talk about "those things" about urinalysis!

Every time I get a medical examination report

Do you often get scared when you see the urine test results?

If “occult blood” is positive, does it mean you have blood in your urine?

If there is a "+" in "urine protein", does it mean that there is a problem with the kidneys?

“Bacterial count” If there is a bacterial count, does that mean you are infected?

NO! NO! NO!

1. Urine color

The urine of a healthy person is usually colorless or light yellow. If the urine color is abnormal, such as meat-washing water, light red, brown, wine, sauce, smoky gray, etc., it is gross hematuria. If there is 1 ml of blood in every 1000 ml of urine, it will appear as meat-washing water and show gross hematuria.

The color of urine is related to the amount of water you drink, the type of diet, the medications you take, and the diseases you have. If you drink a lot of water, your urine can be colorless like water, but if you drink less water or sweat a lot, it can be dark yellow.

Some drugs will also affect the color of urine. For example, after taking rifampicin, rhubarb, senna and other drugs, the urine may appear red; taking vitamin B2 may be accompanied by yellow or dark yellow urine.

Some diseases can also cause changes in urine color, such as strong tea color, soy sauce color, milky white, etc., in which case further examination is needed.

It is especially important to note that red pitaya will also make urine appear red. If your urine turns red, first think about whether you have eaten red food. Don’t scare yourself!

2. Urine occult blood test and red blood cell count

1. Hematuria is often caused by certain diseases of the urinary system, trauma, strenuous exercise, etc., as well as some drugs. For example, taking drugs such as cyclophosphamide is likely to result in positive urine occult blood.

2. Hemoglobinuria is common in cases of vascular hemolysis, severe burns, strenuous exercise and some infections.

3. Common myoglobin-type leukuria, such as muscle injury, muscle wasting disease, dermatomyositis, excessive exercise, etc.

Generally, when the red blood cell count increases, the occult blood test is positive. Normally, human urine contains a small amount of red blood cells, but if the amount exceeds the normal value, it is considered hematuria.

3. White blood cell count

Normal people have a small amount of white blood cells in their urine. Increased counts are common in urogenital inflammation, glomerulonephritis, lupus nephritis, acute interstitial nephritis after acute infection, etc. White blood cells may also increase after strenuous exercise.

4. Urine protein

Qualitative and semi-quantitative urine protein is detected in the urine routine examination. If it is positive, first of all, repeat the test several times to rule out transient proteinuria, because strenuous exercise, fever, dehydration, mental stress and other reasons can cause transient proteinuria, but the degree is relatively mild, generally not more than "++", the duration is not long, and it will disappear after rest; if transient proteinuria is found, multiple tests are positive, it may be an important indication of kidney disease, you must pay attention, you need to see a specialist clinic for further examination and treatment.

5. Urine pH

The alkalinity of urine is around 6.5, and generally fluctuates between 4.5-8.0. The pH value will also change with different diets. Therefore, the pH value of urine also reflects whether one's diet structure is reasonable, and also reflects the kidney's ability to regulate the body's acid-base balance. In addition, infection, gout and drugs can also affect the pH value of urine.

6. Urine Specific Gravity

The fluctuation range of urine specific gravity is 1.015-1.025. This value increase may be mainly caused by glomerulonephritis, diabetes, high fever, heavy sweating, dehydration after acute infection, heart failure, and excessive urine flow; however, decreased urine specific gravity is common in diabetes insipidus, chronic glomerulonephritis, polydipsia, and the polyuria and recovery period of epidemic hemorrhagic fever.

7. Bacteria Count

If the bacterial count increases, a urinary tract infection is considered and the urine white blood cell count will also increase.

8. Urine sugar

A positive urine sugar index indicates that the blood sugar of the diabetic patient is not well controlled. In addition, a positive urine sugar index in a non-diabetic patient is manifested as physiological diabetes such as overeating, stress state, pregnancy, and renal tubular damage, and also as pathological diabetes caused by certain endocrine abnormalities. If a diabetic patient has a positive urine sugar index, it is recommended to combine blood sugar testing during follow-up visits.

9. Precautions for routine urine examination

1. Do not drink a lot of water before the examination, and do not drink colored beverages such as coffee, strong tea, etc.

2. Use a clean, dry container (usually no less than 10 ml of urine, reaching half a urine cup) to collect the urine. The container is usually supplied by the hospital.

3. Collect midstream urine. To avoid interference, usually the beginning and the end are discarded and only the middle part of the urine is collected. If there are special circumstances, the doctor will explain this.

4. The collected urine must be sent for testing within half an hour, and no later than 1 hour.

5. Women should clean their vulva before collecting urine, and try not to do routine urine tests during menstruation. For men with long foreskin, it is best to clean the urethral opening before collecting urine, and it is best to turn the foreskin upwards when collecting urine.

6. If you have taken any medication recently, you should clarify with your doctor in advance.

10. Procedures for Urinalysis

Urinalysis is a simple non-invasive physical examination with the following steps.

Step 1: Preparation

Prepare a disposable urine cup and disposable urine catheter. To avoid bacterial contamination, pay attention to keeping the urethra clean before the examination.

Step 2: Collect urine

Place the urine cup in a clean place and collect the first urine discharged in the morning, about 10-20ml. Be careful not to contaminate the urine and avoid interference from impurities.

Step 3: Check your urine

Just send it for inspection within the specified time.

Step 4: Record the results

The examination results will be recorded on the physical examination form. If any abnormalities are found, appropriate treatment will be given depending on the situation. If necessary, further urine routine examination and urine sediment examination can be performed. (Chen Jing, Beijing West Medical Area, PLA General Hospital)