(A) Comparison of V, however estimated, to itself and to a transformation of V, Vt = 3.27 × V2/3 (see reference 42). (A) Comparison of V, however estimated, to itself and to a transformation of V, Vt = 3.27 × V2/3 (see reference 42). Vt has a curvilinear relationship with V so that Vt is higher than V at low V but lower than V at high V. (B) Illustration of the effect the Vt transformation on Kt/V. The Kt/Vt transformation results in a much higher traditional Kt/V for smaller patients with low V; the Kt/Vt results a lower traditional Kt/V for larger patients with high V. Edmund G. Lowrie CJASN 2009;4:S41-S48 ©2009 by American Society of Nephrology