We assessed total body water (TBW) and extracellular water (ECW) in thirty-four non-ascitic cirrhotics and twenty healthy controls by 2H2O and Br dilution. In the same subjects, bioelectric impedance (BI) was recorded at multiple frequencies. Body hydration was similar for controls (mean 55·6 (SD 6·7)), less-severe cirrhotics (Child-Pugh classification A; CPA; n 21, mean 56·2 (SD 6·2)) and moderately-severe cirrhotics (Child-Pugh classification B; CPB; n 13, mean 57·2 (SD 5·4)). However, intracellular water standardized per litre TBW was significantly higher in CPB subjects (mean 27·0 (SD 7·5); P<0·01) compared with CPA (mean 21·3 (SD 10·6)) and control subjects (mean 18·0 (SD 9·8)). Published formulas for predicting TBW and ECW from BI at multiple frequencies were applied to the cirrhotics. These formulas gave accurate predictions of TBW and ECW, although standard errors of estimates were higher for CPB subjects (TBW ≤ 2·5 and ECW ≤ 2·11) than those for CPA (TBW ≤ 2·0 and ECW ≤ 1·81) and control (TBW 1·4 and ECW 0·9 1) subjects
