Which factor is NOT considered when calculating ultrafiltration rate?

In the context of calculating the ultrafiltration rate during hemodialysis, the primary factors include the total volume of blood processed, the duration of the treatment time, and the desired fluid removal. The ultrafiltration rate is determined by how much fluid needs to be removed from the patient over a specific time frame, which directly relates to both the desired fluid removal and the treatment minutes.

The chemical concentration in the dialysate does play a critical role in the overall dialysis process and can affect the osmotic gradient, but it is not a direct factor in the calculation of the ultrafiltration rate. Ultrafiltration specifically focuses on the movement of fluids across a semipermeable membrane, while the dialysate's chemical composition influences solute clearance rather than fluid removal itself. Hence, it does not contribute to determining the ultrafiltration rate calculation, making it the factor that is not included in this specific calculation.