Hougardy J M, Delanaye P, Le Moine A, Nortier J
Rev Med Brux. 2014 Sep;35(4):250-7.
The accurate estimation of the glomerular filtration rate (GFR) is a goal of multiple interests regarding clinical, research and public health aspects. The strong relationship between progressive loss of renal function and mortality underlines the need for early diagnosis and close follow-up of renal diseases. Creatinine is the commonest biomarker of GFR in use. By reason of non-renal determinants of GFR, it is required to integrate creatinine values within equations that take in account its most important determinants (i.e., age, sex). The CKD-EPI 2009 equation is now recommended as the first line equation to estimate GFR within the general population. In this indication, it should replace MDRD that tends to overestimate the prevalence of stage 3 chronic kidney disease with GFR around 60 ml/min. However, many questions remain about the accuracy of GFR equations in specific situations such as extremes of age or body weight. The identification of new biomarkers, less determined by non-renal determinants, is of importance. Among these biomarkers, cystatin-C is more accurate to estimate GFR when it is combined to creatinine (i.e., equation CKD-EPI 2012). However the indica. tions for using cystatin-C instead of creatinine alone are still unclear and its use remains limited in routine practice. In conclusion, neither biomarker nor equation gives an accurate estimation for the whole range of GFR and for all patient populations. Limits of prediction are relying on both biomarker's properties and the range of GFR that is concerned, but also rely on the measurement methods. Therefore, it is crucial to interpret the estimated GFR according to the strengths and weaknesses of the equation in use.
准确估算肾小球滤过率（GFR）是临床、研究和公共卫生等多个领域共同关注的目标。肾功能进行性丧失与死亡率之间的密切关系凸显了对肾脏疾病进行早期诊断和密切随访的必要性。肌酐是目前临床上最常用的GFR生物标志物。由于GFR存在非肾脏决定因素，因此需要将肌酐值纳入考虑其最重要决定因素（即年龄、性别）的公式中。CKD-EPI 2009公式目前被推荐为一般人群中估算GFR的一线公式。在此应用中，它应取代MDRD公式，后者往往高估了GFR约60 ml/min时3期慢性肾脏病的患病率。然而，在特定情况下，如年龄或体重极端情况，GFR公式的准确性仍存在许多问题。识别受非肾脏决定因素影响较小的新生物标志物具有重要意义。在这些生物标志物中，胱抑素C与肌酐联合使用时（即CKD-EPI 2012公式）估算GFR更为准确。然而，单独使用胱抑素C替代肌酐的指征仍不明确，其在常规实践中的应用仍然有限。总之，无论是生物标志物还是公式，都无法对所有GFR范围和所有患者群体进行准确估算。预测的局限性既取决于生物标志物的特性和所涉及的GFR范围，也取决于测量方法。因此，根据所用公式的优缺点来解释估算的GFR至关重要。
