Relationship between excess fluid, as determined by the difference between measured and estimated body water, and plasma albumin (R = −0.40, P = 0.011). Relationship between excess fluid, as determined by the difference between measured and estimated body water, and plasma albumin (R = −0.40, P = 0.011). A similar amount of variance (12% to 25%) was observed, whichever estimate of fluid status was used: ECW:TBWBIA R = −0.49, P = 0.001; difference in ECW:TBW ratio from normal, (20) R = −0.45, P = 0.002; difference in ECW/Wt from normal, (21) R = −0.35, P = 0.018. Biju John et al. CJASN 2010;5:1463-1470 ©2010 by American Society of Nephrology