In-vivo techniques for determining nephron numberDenic, Aleksandara; Elsherbiny, Hishama; Rule, Andrew D.a,bCurrent Opinion in Nephrology and Hypertension: November 2019 - Volume 28 - Issue 6 - p 545–551 doi: 10.1097/MNH.0000000000000540 DIAGNOSTICS AND TECHNIQUES: Edited by Maarten W. Taal Buy Abstract Author InformationAuthors Article MetricsMetrics Purpose of review Many studies have suggested low nephron endowment at birth contributes to the risk of developing hypertension and chronic kidney disease (CKD) later in life. Loss of nephrons with age and disease is largely a subclinical process. New technologies are needed to count nephrons as glomerular filtration rate (GFR) is a poor surrogate for nephron number. Recent findings Cortical volume, glomerular density, and percent globally sclerotic glomeruli are imperfect surrogates for nephron number. The disector–fractionator method is the most accurate method to count nephrons but is limited to autopsy settings. Glomerular density combined with kidney imaging and ultrafiltration coefficient-based methods require a kidney biopsy, and have been applied in living humans (kidney donors). Low nephron number predicts a higher postdonation urine albumin. Contrast-enhanced MRI has detected glomeruli without a biopsy, but so far, not in living humans. Summary Currently, there is no accurate and well tolerated method for determining nephron number in living humans. A clinically useful method may allow GFR to be replaced by its more relevant determinants: nephron number and single nephron GFR. This could revolutionize nephrology by separating the measurement of chronic disease (nephron loss) from more reversible hemodynamic effects (nephron hyperfiltration/hypofiltration). aDivision of Nephrology and Hypertension bDivision of Epidemiology, Mayo Clinic, Rochester, Minnesota Correspondence to Andrew D. Rule, Mayo Clinic 200 1st St SW, Rochester, MN 55905, USA. Tel: +1 507 266 1045; fax: +1 507 266 7891; e-mail: email@example.com Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.