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.
Sucrose
Mannitol
Inulin
Aminopyrine