Assessment of glomerular filtration rate (GFR) is fundamental to clinical practice, public health, and research. The kidney has several critical functions; GFR is used as an overall assessment of these kidney functions. GFR is used to diagnose, stage, and manage chronic kidney disease (CKD); ascertain the prognosis for chronic kidney disease–related events and mortality; and determine drug dosages. GFR is the rate at which the glomerulus filters plasma to produce an ultrafiltrate and can be assessed from clearance or serum levels of filtration markers. Clearance measurements using exogenous filtration markers are difficult to perform in routine clinical practice, so GFR is more commonly estimated through equations based on serum concentrations of endogenous filtration markers, most commonly creatinine. These GFR estimates are reasonably accurate, but optimal care for patients may require a confirmatory test for a more accurate GFR assessment. Confirmatory tests currently available include cystatin C–based equations, urinary or plasma clearance of exogenous filtration markers, or urinary clearance of creatinine. Appreciation of the concept of GFR and methods for optimal assessment in routine practice or special circumstances, and their strengths and limitations, are critical in making judicious use of the available tools.

肾小球滤过率 (GFR) 的评估是临床实践、公共卫生和研究的基础。肾脏有几个关键功能；GFR 被用作对这些肾功能的总体评估。GFR 用于诊断、分期和管理慢性肾病 (CKD)；确定慢性肾脏病相关事件和死亡率的预后；并确定药物剂量。GFR 是肾小球过滤血浆以产生超滤液的速率，可以通过过滤标志物的清除率或血清水平进行评估。使用外源性滤过标志物的清除率测量在常规临床实践中难以进行，因此 GFR 更常见的是通过基于内源性滤过标志物（最常见的是肌酐）的血清浓度的方程来估计。这些 GFR 估计值相当准确，但对患者的最佳护理可能需要验证性测试才能更准确地评估 GFR。目前可用的验证性测试包括基于胱抑素 C 的方程式、外源性过滤标志物的尿液或血浆清除率，或肌酐的尿液清除率。了解 GFR 的概念和在常规实践或特殊情况下进行最佳评估的方法，以及它们的优势和局限性，对于明智地使用现有工具至关重要。