The glomerular filtration rate (GFR) is a critical marker of kidney function, reflecting the efficiency of filtration by the glomeruli. Renal clearance of specific substances, such as inulin or creatinine, is commonly used to measure GFR.

Renal clearance refers to the volume of plasma cleared of a specific substance, such as creatinine, per unit of time. To measure clearance, urine samples are collected over a 24-hour period during each bladder voiding, followed by a single blood sample at the end of the interval. The renal clearance of a substance is calculated using the formula:

Clearance (C)= [Urine Concentration (U) x Urine Flow Rate (V)]/Plasma Concentration (P)

This measurement is typically expressed in milliliters per minute (mL/min).

A substance's renal clearance provides insight into how effectively it is removed from the plasma: High renal clearance indicates that the substance is efficiently eliminated, either through filtration or active secretion. Low renal clearance suggests minimal removal, which may result from reabsorption, reduced filtration, or limited secretion. For instance: Glucose has a clearance of zero, as it is completely reabsorbed under normal physiological conditions. Inulin clearance equals GFR, as inulin is freely filtered and neither reabsorbed nor secreted. This makes inulin the gold standard for GFR measurement.

While inulin is ideal for measuring GFR, creatinine clearance is often used in clinical practice due to its practicality. Muscle metabolism produces creatinine at a relatively constant rate, it is freely filtered, and it has minimal tubular reabsorption or secretion. Although creatinine clearance slightly overestimates GFR due to some secretion, it remains a reliable and convenient marker for assessing kidney function.

Renal clearance provides a quantitative measure of kidney function by determining how efficiently a substance is removed from plasma. GFR, calculated using substances like inulin or creatinine, serves as a vital indicator of renal health, enabling early detection and management of kidney disorders.

来自章节 29:

article

Now Playing

29.19 : Renal Clearance

The Urinary System

153 Views

article

29.1 : 泌尿系统简介

The Urinary System

419 Views

article

29.2 : 肾脏的外部解剖结构

The Urinary System

231 Views

article

29.3 : 肾脏内部解剖

The Urinary System

269 Views

article

29.4 : 肾脏的血液和神经供应

The Urinary System

173 Views

article

29.5 : 肾单位

The Urinary System

556 Views

article

29.6 : 肾小体

The Urinary System

321 Views

article

29.7 : 肾小管和集合管

The Urinary System

294 Views

article

29.8 : 尿液形成的生理学

The Urinary System

604 Views

article

29.9 : 肾小球滤过

The Urinary System

349 Views

article

29.10 : 肾小球滤过:净过滤压力

The Urinary System

320 Views

article

29.11 : 肾小球滤过率及其调节

The Urinary System

625 Views

article

29.12 : 肾小管重吸收和分泌

The Urinary System

121 Views

article

29.13 : PCT 中的重吸收和分泌

The Urinary System

268 Views

article

29.14 : Henle 袢中的重吸收和分泌

The Urinary System

280 Views

See More

JoVE Logo

政策

使用条款

隐私

科研

教育

关于 JoVE

版权所属 © 2025 MyJoVE 公司版权所有,本公司不涉及任何医疗业务和医疗服务。