A plasma creatinine- And urea-based equation to estimate glomerular filtration rate in rats

Paul J. Besseling, Tobias T. Pieters, Isabel T. N. Nguyen, Petra M. de Bree, Nel Willekes, Adele H. Dijk, Dominique M. Bovée, Ewout J. Hoorn, Maarten B. Rookmaaker, Karin G. Gerritsen, Marianne C. Verhaar, Hendrik Gremmels, and Jaap A. Joles

Published: 2021


Monitoring renal function is a vital part of kidney research involving rats. The laborious measurement of glomerular filtration rate (GFR) with administration of exogenous filtration markers does not easily allow serial measurements. Using an in-house database of inulin clearances, we developed and validated a plasma creatinine- and plasma urea-based equation to estimate GFR in a large cohort of male rats [development cohort n = 325, R2 = 0.816, percentage of predictions that fell within 30% of the true value (P30) = 76%] that had high accuracy in the validation cohort (n = 116 rats, R2 = 0.935, P30 = 79%). The equation was less accurate in rats with nonsteady-state creatinine, in which the equation should therefore not be used. In conclusion, applying this equation facilitates easy and repeatable estimates of GFR in rats.NEW & NOTEWORTHY This is the first equation, that we know of, which estimates glomerular filtration rate in rats based on a single measurement of body weight, plasma creatinine, and plasma urea.

Full Access Link: American Journal of Physiology - Renal Physiology