The mechanism of morphological formation of urinary anomalous red blood cells Zhu Xianggang, Department of Nephrology, Beijing Hospital of Traditional Chinese Medicine At present, it is generally believed that the possible mechanisms are: (1) red blood cells are damaged by extrusion through the glomerular filtration membrane with pathological changes; (2) red blood cells are affected by renal tubular filtrate with continuous changes in pH and osmotic pressure: in nephrogenic hematuria, because the red blood cells themselves are damaged, their morphology has already changed, and therefore they are highly susceptible to changes in pH and osmotic pressure of renal tubular filtrate. changes in the pH and osmolality of the renal tubular filtrate and are therefore highly susceptible to morphological aberrations. In non-nephrogenic hematuria, the premise of extrusion damage of red blood cells through the glomerular membrane does not exist, and the red blood cells flow through the tubular filtrate for a short period of time and are therefore less affected by changes in pH and osmotic pressure of the filtrate, so the morphology of red blood cells remains normal or mildly changes in homogeneity. Hematuria is a common clinical sign of the urinary system. Depending on the amount of bleeding, it can be divided into 1) visual hematuria and 2) microscopic hematuria. Clinically, microscopic hematuria in transient or intermittent episodes is mostly physiological; if the hematuria is persistent, it suggests pathological changes. Microscopic examination of urine is easy to obtain, especially for early detection of diseases of the urinary system, and thus continues to be an important item in routine clinical examination. I. The concept of hematuria After examining 10 fields of view with conventional urine centrifugal sediment slide smears at high magnification 400 times, if more than 3 to 5 red blood cells are seen in each high magnification field, it is designated as microscopic hematuria. In fact, a certain number of urinary red blood cells are also present in normal human urine. The observation of the number of erythrocytes in normal urine is not consistent among different authors. (i) With high magnification expression there are: 0 to 2/HPF, 3 to 5/HPF, 1 to 8/HPF, etc. (ii) Expressed as 12h urine erythrocyte count, there are Addis (1926): <425000/12h; other scholars: <600000/12h (equivalent to 2/HPF or 5000/ml urine), etc. ③ Expressed as 24h urine red blood cell count, with 1.2×106/24h urine, <1.0×106/24h urine, etc. ④ Expressed as erythrocytes per ml of urine, there are: <8000/ml, <5000/ml; 500-5000/ml, children <14000/ml urine, etc. Any exceed the above range, are considered pathological hematuria. Red blood cell morphology in urine 1. Renal hematuria refers to the presence of ① size change, ② abnormal morphology, ③ changes in the distribution and content of hemoglobin in red blood cells. The presence of at least two types of red blood cell morphology in renal hematuria is also called polymorphic hematuria or non-homogeneous hematuria. The common ones are: serrated (crumpled), ring-shaped (bagel-like), mouth-shaped, shadow-shaped, fissured, bell-shaped, and spiny (whose morphology appears to be based on ring-shaped red blood cells accompanied by cytoplasmic vesicular protrusions, described by some as gourd-like protrusions, yeast-like germination-like protrusions, and Mickey Mouse ear-like.) Kohler found that spiny red blood cells have a specific morphology and, therefore, are easy for observers to recognize, and their number is > Kohler also believes that in the renal unit environment, such echinococytes appear only when hemolysis occurs, while in healthy individuals or in non-renal disease, they are almost never seen. 2, non-renal hematuria refers to the morphological consistency of red blood cell size in a single form of normal red blood cells, in a few cases, can be slightly altered due to factors such as urinary pH or osmolality serrated cells or shadow cells. At present, it is generally believed that the possible mechanisms are: (1) the red blood cells are damaged by extrusion through the glomerular membrane with pathological changes; (2) the red blood cells are affected by the renal tubular filtrate with different pH and osmolarity changes: in nephrogenic hematuria, because the red blood cells themselves are damaged, their morphology has been changed, so they are highly susceptible to the influence of changes in pH and osmolarity of the renal tubular filtrate and undergo Morphological aberrations. Non-nephrogenic hematuria does not have the premise that red blood cells are damaged by extrusion through the glomerular membrane, and the red blood cells flow through the renal tubular filtrate for a short period of time, so they are less affected by changes in the pH and osmotic pressure of the filtrate, so the red blood cell morphology remains normal or mildly changes in homogeneity. The clinical significance of red blood cell morphology in identifying hematuria The importance of differentiating renal and non-renal hematuria ①Nephrogenic hematuria: Since it mainly involves renal parenchymal lesions, once the screening test establishes that it is renal hematuria, further tests are usually urine protein tubing, renal function measurement, renal biopsy, etc. (2) Non-renal hematuria: Once established, further investigations focus on cystoscopy and CT examination, etc. The main renal hematuria diseases are: membranous glomerulonephritis, IgA nephropathy, lupus nephritis, focal nephrosclerosis, systemic vasculitis, renal amyloidosis, etc. The main non-renal hematuria diseases are: renal calculus, urethral tumor, prostatic hypertrophy, etc. Diagnostic criteria for renal and non-renal hematuria: There is no definite conclusion, and the definition differs among authors. Some consider heterogeneous red blood cells accounting for 80% as renal, while normal homogeneous form red blood cells accounting for more than 90% as non-renal. Most authors believe that heterogeneous erythrocytes above 75% are renal, while <20% are non-renal disease. V. Conclusion Erythrocytes can be easily identified with phase contrast microscopy, but only with fresh urine specimens. roth preserves urine specimens with Thimerosal (thimerosal), which keeps the erythrocyte morphology in the specimen intact for at least 3 days, thus allowing it to be used for routine testing to improve the early diagnosis of glomerulonephritis. In conclusion, urine erythrocyte morphology is clinically important for the early identification of renal and non-renal disease.