Kt/V

In medicine, Kt/V is a number used to quantify hemodialysis and peritoneal dialysis treatment adequacy.Body water: Intracellular fluid/Cytosol In medicine, Kt/V is a number used to quantify hemodialysis and peritoneal dialysis treatment adequacy. In the context of hemodialysis, Kt/V is a pseudo-dimensionless number; it is dependent on the pre- and post-dialysis concentration (see below). It is not the product of K and t divided by V, as would be the case in a true dimensionless number. In peritoneal dialysis, it isn't dimensionless at all. It was developed by Frank Gotch and John Sargent as a way for measuring the dose of dialysis when they analyzed the data from the National Cooperative Dialysis Study. In hemodialysis the US National Kidney Foundation Kt/V target is ≥ 1.3, so that one can be sure that the delivered dose is at least 1.2. In peritoneal dialysis the target is ≥ 1.7/week. Despite the name, Kt/V is quite different from standardized Kt/V. K (clearance) multiplied by t (time) is a volume (since mL/min × min = mL, or L/h × h = L), and (K × t) can be thought of as the mL or L of fluid (blood in this case) cleared of urea (or any other solute) during the course of a single treatment. V also is a volume, expressed in mL or L. So the ratio of K × t / V is a so-called 'dimensionless ratio' and can be thought of as a multiple of the volume of plasma cleared of urea divided by the distribution volume of urea. When Kt/V = 1.0, a volume of blood equal to the distribution volume of urea has been completely cleared of urea. The relationship between Kt/V and the concentration of urea C at the end of dialysis can be derived from the first-order differential equation that describes exponential decay and models the clearance of any substance from the body where the concentration of that substance decreases in an exponential fashion: