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URR

URR: calculated with the published clinical method, with result interpretation. A reference tool that does not replace a doctor's advice.

ℹ Reference calculation based on the published method. It does not replace a clinical examination or a doctor's decision.

URR

Pre-dialysis ureammol/L
Post-dialysis ureammol/L
Session lengthh
UltrafiltrationL
Post-dialysis weightkg
URR
68%
URR: calculated with the published clinical method, with result interpretation. A reference tool that does not replace a doctor's advice.
URR assessment
Adequate dialysis (≥ 65%)
spKt/V (Daugirdas II)
1.33

More about: URR

What it calculates

The “URR” calculator computes URR in % from 5 parameters: pre-dialysis urea (mmol/L), post-dialysis urea (mmol/L), session length (h), ultrafiltration (L), post-dialysis weight (kg).

Used by professionals and patients to assess health metrics, dosages, and risks.

Example calculation

With parameters Pre-dialysis urea = 25 mmol/L, Post-dialysis urea = 8 mmol/L, Session length = 4 h, Ultrafiltration = 2 L, Post-dialysis weight = 70 kg the result is 68 %.

How to use

  1. Enter pre-dialysis urea, post-dialysis urea, session length, ultrafiltration and post-dialysis weight — each field above is adjustable with a slider.
  2. URR (%) is calculated automatically as you type.
  3. Check the worked example below to see the formula applied to real numbers.
  4. Copy the result or bookmark this calculator.

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FAQ

How is BMI calculated?
BMI = weight (kg) / height (m)². Example: 70 kg / (1.75 m)² = 22.9. The WHO normal range is 18.5–24.9; below that is underweight, 25–29.9 is overweight, and 30+ is obese.
Is BMI accurate for everyone?
No. BMI does not distinguish muscle from fat, so athletes may show a high BMI with low body fat. It is also less reliable for teenagers, pregnant people, older adults, and very tall or short individuals.
What are the BMI categories?
Underweight: below 18.5. Normal: 18.5–24.9. Overweight: 25–29.9. Obese class I: 30–34.9; class II: 35–39.9; class III: 40+.
What is a better measure than BMI?
Body fat percentage, waist-to-height ratio (aim for under 0.5), and waist circumference give a clearer picture of health than BMI alone.

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