The effect of fluid deprivation, antidiuretic hormone and forced fluid intake on 51-Cr-EDTA clearance

The effect of fluid deprivation, antidiuretic hormone (DDAVP) and forced fluid intake on glomerular filtration rate (GFR) was studied in 41 healthy males by determining 51-Cr-EDTA clearance after a single bolus injection. GFR was the same on forced and on free fluid intake. A small, clinically insignificant decrease in GFR (-6.5%), compared to values on free fluid intake, was registered during the periods of fluid deprivation plus DDAVP. There seem to be no objections to combining a clearance study with a concentrating ability test when screening groups of subjects with normal or near normal GFR.