What should I do if the physical examination finds occult blood in the urine (+)?
In the physical examination, the urine routine is a simple, convenient and effective test that can detect kidney disease early. However, people often feel nervous and anxious when they see "occult blood in the urine (+)" in the urine routine report or when they notice that the urine is red. Let's take a closer look at the knowledge of "occult blood in the urine" so that we can better understand and deal with it.
What is hematuria?
Hematuria is a common manifestation of kidney disease, but it is more insidious, such as normal urine color, and is usually detected during physical examination. Hematuria is divided into two conditions: gross hematuria and microscopic hematuria.
When more than 1 ml of blood is found in every 1000 ml of urine, it is called gross hematuria, and in severe cases, it is like washing water, with or without blood streaks and blood clots.
If the urine is normal in appearance, but the urine is centrifuged and the number of red blood cells per high-power field exceeds 3, it is called microscopic hematuria.
There are many causes of hematuria, 95%~98% of hematuria is caused by urinary system diseases, and a few are caused by systemic diseases or lesions of adjacent organs of the urinary system.
When the physical examination reveals positive urine occult blood,
The first step is to determine whether there is true hematuria
Urine occult blood is based on the reaction of the hemoglobin in the urine with the reagent on the test strip, and the color change is used to determine whether it is positive.
The test is highly affected by external factors, such as taking iron-containing drugs, animal blood, animal liver, lean meat, and a large amount of green vegetables or supplementing with vitamin C supplements before the test, which may cause false positive results.
In addition, strong oxidants in the urine (such as the residual oxidants from the vulva), a large number of bacteria, and male semen contamination can also cause changes in the color of the test strips, and the color of the test strips can be caused by the filtration of hemoglobin produced by intravascular hemolysis into the urine or the filtration of myoglobin produced by muscle damage into the urine.
Red urine does not necessarily mean hematuria, it can also be red when certain foods (such as beets, peppers, tomato leaves) or certain medications (such as rifampicin, phenytoin, indomethacin, rhubarb, etc.) are mixed with blood (menstrual pollution, hemorrhoidal bleeding, etc.).
Therefore, when urinary occult blood (+) is present, the above conditions should be excluded in the first place. There are also cases of "physiological hematuria", such as:
01
Healthy people usually exercise less, and after a sudden increase in exercise, there may be transient "hematuria", but no cause can be found, which is called "exercise-induced hematuria".
02
Holding urine for too long and the bladder continues to fill and congest, causing capillaries to rupture.
03
In adolescent males, the penis becomes erect at night, which may cause damage to the capillary wall and cause the morning urine to test for "hematuria".
04
Tall, thin adolescents will have "orthostatic hematuria" that disappears when lying down.
All of the above conditions do not require special treatment and treatment, and can be rechecked at intervals, and the "hematuria" often disappears spontaneously.
Positive only for urine occult blood
A normal number of red blood cells in the urine is not hematuria
After the true hematuria is identified, it is necessary to further determine whether the red blood cells come from the kidneys or extranephrals?
A second test, called a phase contrast microscopy of urine sediment, is done. Red blood cells derived from the kidney, due to the extrusion of the glomerular filtration membrane, often lose their normal morphology and become ring-shaped, target-shaped, spore-shaped or shriveled, called malformed red blood cells.
If the malformed red blood cells are more than 80%, it is considered that the red blood cells come from the kidneys, which is called nephrogenic hematuria, which is common in kidney diseases, such as acute and chronic glomerulonephritis, hypertensive nephropathy, lupus nephritis, etc.;
After determining whether the hematuria is from the kidneys or other parts, the doctor will combine the patient's clinical symptoms and perform necessary auxiliary examinations, such as B-ultrasound, CT, etc., to determine the cause of hematuria. Based on the results, the doctor will treat the symptoms on a case-by-case basis.
Therefore, if you have a result of "occult blood in the urine (+)" in your physical examination report, don't panic first, positive for occult blood in the urine ≠ hematuria. To find a specialist for review: first determine whether it is "hematuria", further determine whether it is pathological "hematuria", determine the cause, and then treat the symptoms, for friends who have suffered from urological diseases (such as kidney disease, stones, urinary infections, etc.), it is also recommended that you have regular physical examinations, monitoring and re-examination, and specialist follow-up.
About the author: Xue Yu
Xue Yu
Department of Nephrology, Beijing Geriatric Hospital
Attending
He has been engaged in nephrology for more than 10 years, and is good at the diagnosis and treatment of common nephrology diseases such as urinary tract infection, diabetic nephropathy, hypertensive nephropathy, nephrotic syndrome and end-stage renal disease, and has rich clinical experience in the standardized treatment of renal anemia and renal bone disease in hemodialysis patients.
Beijing Geriatric Hospital Association for Science and Technology
Author|Xue Yu
Typography | Ni Ni
审核 | 一涵 六朵 慧 陨石 竹子
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