What does Kt/V measure in dialysis adequacy?

• A. The dialysis dose, representing clearance (K) times time (t) divided by the volume of distribution (V) of urea.
• B. The patient's blood pressure during dialysis.
• C. The temperature of the dialysate.
• D. The rate of IV fluids.

Answer: (A)

Kt/V measures how much urea is removed during a dialysis session relative to the patient's body size. K is the dialyzer’s clearance of urea, t is the treatment time, and V is the volume of distribution of urea (roughly the total body water). The ratio, Kt/V, is a unitless value that reflects the effectiveness of the dialysis dose for that patient—higher values indicate more adequate clearance for that body size. This concept helps clinicians decide if a session provides enough dialysis by comparing the actual clearance to the patient’s body water; it’s not related to blood pressure, dialysate temperature, or IV fluid rate.