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Updated: May 13, 2026

Transcutaneous Assessment of Renal Function in Conscious Rodents
Published on: March 26, 2016
Rapid assessment of renal reserve in young adults by cystatin C
Dana Y Fuhrman1, Paula S Maier1, George J Schwartz1
1a Pediatric Nephrology, University of Rochester Medical Center , Rochester, NY USA.
Background:
The kidney can increase glomerular filtration rate (GFR) in response to a protein load (renal reserve). In a pilot study of healthy young adults we examined renal reserve using changes in serum cystatin C (cysC).
Methods:
Glomerular filtration rate was obtained using iohexol single slope plasma disappearance. To stimulate GFR, subjects ingested a beefburger containing 60 grams of protein. CysC was measured by immunonephelometry before and 125-141 minutes after protein loading.
Results:
All subjects were found to have a normal iohexol plasma disappearance GFR with a mean of 104.6 ± 9.9 mL/min per 1.73 m(2). CysC decreased in each subject after the meat meal. Baseline cysC-based estimated GFR was 98.1 ± 9.1 mL/min per 1.73 m(2) with a mean increase of 12.0 ± 5.2 (p = 0.0003).
Conclusions:
Our study showed a consistent decrease in serum cysC and increase in cysC-based estimated GFR following a protein load in young adults. Further studies are needed using renal clearance methods to confirm that cysC accurately determines renal reserve in patients with and without chronic kidney disease.
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