The kidney is the "detoxification filter" of the human body, responsible for removing waste and excess water from the blood and maintaining metabolic balance in the body. Due to the subtle symptoms of early kidney disease, it is often referred to as the "silent killer".
Professor Chen Wen, director of the Nephrology Department at Hainan Chengmei Hospital, reminds that the first urine after getting up in the morning is the most intuitive "barometer" reflecting kidney health. If any of the following three situations occur, it is necessary to seek medical examination in a timely manner.
01 Fine and dense foam that persists for a long time: be alert to proteinuria
Normal urine will generate a small amount of foam due to the impact force of urination, but the foam is large and sparse, and it will completely dissipate within a few seconds to 1 minute after being left undisturbed.
If fine, uniform small foam appears in the morning urine, resembling beer foam or laundry detergent water, covering the surface of the urine and not dissipating after being left undisturbed for more than 10 minutes, it is highly indicative of proteinuria.
Professor Chen Wen explained that the glomerular filtration membrane of a healthy kidney acts like a "fine sieve", capable of preventing proteins in the blood from leaking into the urine. When the filtration membrane is damaged (such as in glomerulonephritis, diabetic nephropathy, or hypertensive renal damage), a large amount of protein leaks out, altering the surface tension of the urine and forming persistent foam.
This foam in the urine is not a sign of "excessive internal heat" or insufficient water intake, but rather a typical indication of impaired kidney filtration function. If it persists for more than 3 days, it is necessary to immediately undergo urine routine examination and 24-hour urine protein quantitation.
02 Reddish urine color / Strong tea color: Warning of hematuria
Normal morning urine is concentrated during the night and appears light yellow to dark amber in color, which gradually becomes lighter after drinking water. If the urine color is abnormal, such as appearing like washed meat water, pink, bright red, or dark brown like strong tea or soy sauce, and if the consumption of red dragon fruit, beet, or the use of drugs such as rifampin or phenolphthalein the day before is ruled out, it can generally be determined as hematuria.
There are two types of hematuria: gross hematuria (urine is visibly red) and microscopic hematuria (urine color is normal, but there are excessive red blood cells under a microscope).
Professor Chen Wen pointed out that painless hematuria is more dangerous and may be a signal of diseases such as glomerulonephritis, kidney cancer, and bladder cancer; if hematuria is accompanied by low back pain, urinary frequency, and urgency, it is often related to kidney stones and pyelonephritis.
In any case, hematuria indicates damage and bleeding in the kidneys or urinary tract mucosa, which must not be ignored.
03 Sudden changes in urine volume, turbidity, and unusual odor: Be alert to abnormal renal function
The morning urine volume of a healthy adult is approximately 300-500ml (equivalent to 1-2 paper cups), and the total urine volume over 24 hours is 1000-2000ml. Director Chen Wen emphasized that a sudden significant change in urine volume is an important signal of abnormal kidney function:
Excessively low urine output: If the morning urine output is less than 100ml, or the 24-hour urine output is less than 400ml (oliguria) or less than 100ml (anuria), accompanied by edema in the lower limbs and eyelids, it may indicate acute kidney injury, chronic kidney failure, or urinary tract obstruction, where the kidneys are unable to drain and detoxify normally.
Excessive urine output: morning urine output exceeding 800ml, or 24-hour urine output >2500ml, with nocturia ≥3 times. Excluding excessive water intake before bedtime, it may indicate impaired renal tubular concentration function or early diabetic nephropathy.
In addition, severe turbidity of urine, resembling rice water, or the presence of white flocculent precipitates and a foul odor, are often indicative of urinary system infections (such as pyelonephritis). If the infection persists for a long time, it can damage the renal parenchyma and induce chronic kidney disease.
Experts remind: Regular kidney examinations are crucial for three high-risk groups
The prevalence of chronic kidney disease in China stands at 10.8%, yet the awareness rate is less than 13%. Many patients are diagnosed with the disease at an advanced stage. Professor Chen Wen advises that, besides monitoring changes in morning urine, three high-risk groups should undergo urine routine tests, renal function tests, and kidney ultrasound examinations every 3-6 months.
01 Patients with chronic diseases
Patients with diabetes, hypertension, and hyperlipidemia may experience long-term hyperglycemia and hypertension, which can damage the renal microvasculature and induce diabetic nephropathy and hypertensive renal damage;
02 Long-term medication users
Individuals who regularly consume analgesics, antibiotics, traditional remedies, and health supplements may experience an increased burden on their kidneys due to drug toxins
03 Other high-risk groups
Individuals with a family history of kidney disease, recurrent urinary tract infections, a habit of holding urine for extended periods, and a diet high in salt and protein face a significantly higher risk of developing kidney disease compared to the general population.
The nephrology expert team at Hainan Chengmei Hospital reminds that early detection and intervention are crucial for preventing kidney diseases. If there are abnormalities in the morning urine, such as foam, color, or urine volume, do not delay or self-medicate. Instead, seek timely examination at a reputable hospital's nephrology department to maintain kidney health.
Expert Introduction
Chen Wen, Director of Nephrology Department
Chief Physician, Professor, Master's Supervisor
Outstanding experts with exceptional contributions in Hainan Province
Leading talents in Hainan Province
Key experts directly connected with the Provincial Party Committee and Provincial Government of Hainan Province
Medical expertise
Skilled in treating primary glomerular disease, IGA nephropathy, lupus nephritis, hypertensive nephropathy, uric acid nephropathy, and diabetic nephropathy; especially proficient in the diagnosis and treatment of critical and complex diseases, as well as clinical pathological diagnosis and treatment in nephrology; proficient in the diagnosis and treatment of indications and complications of hemodialysis and peritoneal dialysis; proficient in the establishment of temporary and long-term vascular dialysis access and peritoneal dialysis access, as well as the management of complications.