How to Use Kt/V Calculator (Daugirdas)
The Kt/V Calculator (Daugirdas) is a dialysis adequacy calculator based on the second-generation Daugirdas structure used for urea kinetics. The calculator exposes the Daugirdas components instead of only showing the final Kt/V, making the BUN ratio and UF correction easy to audit.
Enter pre-dialysis BUN, post-dialysis BUN, dialysis time in hours, ultrafiltration volume in liters, and post-dialysis weight in kilograms. Use matched pre- and post-dialysis BUN samples from the same treatment. Ultrafiltration is entered in liters and post-dialysis weight in kilograms.
The result displays Kt/V, the post/pre BUN ratio R, the logarithmic term, and the UF/W correction term. Post-dialysis BUN must be lower than pre-dialysis BUN for a valid reduction ratio. The logarithm term is also checked so the formula stays mathematically defined.
Formula & Theory - Kt/V Calculator (Daugirdas)
The Kt/V Calculator (Daugirdas) uses this formula or scoring rule:
Kt/V = -ln(R - 0.008 × t) + (4 - 3.5 × R) × UF / WPost-dialysis sampling technique and timing strongly affect the BUN ratio. Adequacy targets vary by patient and dialysis prescription, so the result should be reviewed with the dialysis team.
Small errors in post-dialysis sampling can produce large Kt/V changes. Recirculation, rebound, access issues, and residual kidney function may all affect adequacy interpretation.
Use Cases for Kt/V Calculator (Daugirdas)
The Kt/V Calculator (Daugirdas) is especially useful for:
- checking a dialysis adequacy worksheet
- teaching how R, time, and ultrafiltration enter Daugirdas Kt/V
- testing how longer treatment affects the estimate
- reviewing monthly dialysis lab examples
Use the result to verify a dialysis worksheet or teach the formula. Prescription changes should be handled by the dialysis team using the full clinical picture.