ECF volume assessment can be done most accurately by

Indicators used for fluid volumes 1.       Total body water (TBW)- Deuterium Oxide D2O, Tritium oxide, Aminopyrine, Antipyrine 2.       ECF- Inulin, Sucrose, Mannitol, Sodium thiosulphate, Na22 3.       Plasma volume- Evan’s blue, radioactive iodine labelled serum albumin (I125)   4.       Blood cell volume- Cr51 labelled RBC The most accurate indicator for ECF volume assessment is Inulin.