D2O is used to determine-
Volume Indicators Total body water 3H2O, 2H2O, Antipyrine Extracellular fluid 22Na, 125I-iothalamate, thiosulphate, inulin ICF (calculated as TBW-ECF) Plasma volume 125I-albumin, Evans blue dye Interstitial fluid (calculated as ECF-plasma volume) Blood volume Cr-labeled red blood cells
ICF
ECF
Total body water
Plasma volume
Body fluid compaments