What Are the Indicators Reflecting the Function of Glomerular Filtration?

The most reliable indicator reflecting glomerular filtration function is glomerular filtration rate, commonly known as GFR. Glomerular filtration rate refers to the amount of filtrate formed by both kidneys per unit time, generally around 125ml/min for normal adults. However, due to the difficulty of clinically measuring glomerular filtration rate, endogenous creatinine clearance is often used instead to reflect the function of glomerular filtration. The normal indicator of endogenous creatinine clearance is between 80-120ml/min. In addition, cystatin C is also used clinically to reflect the glomerular filtration function, as it is relatively stable and sensitive, unaffected by external factors such as age, weight, and gender.

Abnormal renal function: In the early stages of the disease, glomerular filtration rate may decrease, leading to water and sodium retention and reduced urine output. In a few patients, oliguria may even occur. Only a very small number of patients may present with acute renal failure, which can be easily confused with rapidly progressive glomerulonephritis. Rapidly progressive glomerulonephritis is characterized by the early appearance of oliguria, anuria, and rapid deterioration of renal function, in addition to acute nephritic syndrome. When it is difficult to distinguish between severe acute nephritis presenting with acute renal failure and this disease, renal biopsy should be performed promptly for diagnosis. In chronic glomerulonephritis, glomerular filtration rate and endogenous creatinine clearance decrease, blood urea nitrogen and creatinine increase, renal function is mostly in the compensatory or decompensatory stage, and phenol red excretion test and urine concentration and dilution function are both decreased.

The amount of filtrate produced by both kidneys per unit time is called glomerular filtration rate (GFR), which is approximately 125ml/min for normal adults. The ratio of glomerular filtration rate to renal plasma flow is called the filtration fraction. Adults can produce up to 180L of original urine per day and night, but the final urine volume excreted daily is only 1-2L. This indicates that approximately 99% of the water is reabsorbed back into the blood during the passage of the original urine through the renal tubules and collecting ducts. Furthermore, there are significant differences between the final urine and the original urine in terms of composition. For example, the original urine contains glucose, while the final urine does not; whereas the final urine contains more creatinine and ammonia than the original urine. This demonstrates that the original urine must undergo the function of the renal tubules and collecting ducts to produce the final urine.