URR (urea reduction ratio) measures the fractional reduction in blood urea nitrogen during a hemodialysis session. Formula: URR = (pre-BUN minus post-BUN) / pre-BUN x 100%.

What URR target is recommended?

KDOQI guidelines recommend URR > 65% as a minimum adequacy target. URR and Kt/V are complementary measures; Kt/V is generally considered more accurate.

How does URR differ from Kt/V?

URR is simpler to calculate but does not account for ultrafiltration volume or convective urea removal, making it less accurate than Kt/V in patients with high fluid removal.

Urea Reduction Ratio (URR) Calculator

Calculate the urea reduction ratio (URR) to assess hemodialysis adequacy. URR = (pre-BUN minus post-BUN) / pre-BUN x 100. Target > 65%.

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Frequently Asked Questions

What is URR?

What URR target is recommended?

How does URR differ from Kt/V?