The Introduction of Creatinine Clearance to Estimate Kidney Function

In 1914, Thomas Addis famously remarked that all we know for certain about the kidney is that it makes urine. More than a reflection of humility, this statement captured the state of uncertainty regarding kidney physiology at the time. Over a decade later in 1926, Poul Brandt Rehberg submitted his doctoral thesis, Studies on Kidney Function, where he described a method to measure the GFR. This Perspective marks the 100-year anniversary of Poul Brandt Rehberg's dissertation, wherein he introduced creatinine clearance as a method to estimate GFR and made critical contributions toward understanding the mechanisms underlying urine formation