[Exploration of renal glomerular function: estimation of glomerular filtration rate]

In addition to direct measurement methods of glomerular filtration rate, there are many formulas whose purpose is to estimate glomerular filtration rate from endogenous markers, of which the most used is serum creatinine. The latest recommendations the French health agency Haute Autorité de santé (HAS) unambiguously endorse the use of the CKD-EPI equation. The assessment of glomerular filtration rate from this equation however remains approximate in many situations where the plasma creatinine concentration poorly reflects the glomerular filtration rate. In these situations, plasma cystatin C could potentially be a more reliable alternative to endogenous plasma creatinine marker, especially since a reference standard for the determination of serum cystatin C concentration has recently been developed. Use of serum cystatin C concentration in clinical practice begins to be mentioned, but still needs to be fully validated.