For those who have kidney disease or renal failure, it is crucial to learn about the URR Calculator. Chronic kidney diseases affect nearly 15% of the adult population worldwide. However, what is even more alarming is that only 10% of people who have chronic kidney diseases are aware that they have such conditions. Not everyone has access to treatments and medical care in most countries, so it is essential to know how to calculate URR at home from time to time.

The formula for calculating URR is fairly straightforward and can be done easily with any modern calculator app.

What is urea?

Urea is a waste product of protein metabolism that is produced by the liver and excreted in the urine. When you eat, your body breaks down food into the basic building blocks it needs to function— carbohydrates, proteins, fats, etc. The process of breaking down proteins results in urea being formed as a waste product. Urea is removed from your blood by the kidneys and then excreted in your urine if there are no other substances present which inhibit or delay this process (such as coffee or alcohol).

What does URR stand for, and how to use it?

URR stands for Urea Reduction Ratio and can be thought of as the ratio of urea concentrations in the blood and dialysate. It is calculated by dividing the concentration of urea in the dialysate by that found in the blood. The higher your URR, the greater your body’s ability to remove urea from your blood.

History and overview URR

URR is a measure of dialysis adequacy and efficiency. It’s an important concept in the world of renal care, so let’s take a moment to learn more about it.

Urea reduction ratio (URR) is a measure used in renal failure patients to determine how much urea has been removed during dialysis. Urea is one type of nitrogen-containing waste that builds up in your bloodstream when you have kidney problems. A low URR indicates that there’s plenty of urea left after the filtration process, which means there could be some room for improvement in your treatment plan or equipment set-up!

How to calculate URR in dialysis?

When you’re calculating the URR, it’s important to know that it takes approximately 4 hours for a patient’s serum creatinine to return to normal after a dialysis session. This means that if you are using an estimated pre-dialysis serum creatinine value, you will have to calculate the URR using your actual post-dialysis serum creatinine value once 4 hours have passed.

To calculate the urea reduction ratio using our calculator, enter your pre-dialysis and post-dialysis values into the blanks provided. You’ll see how much urea was removed during dialysis by looking at the results of this equation:

\text {URR} = \frac {\text {Post-Dialysis Creatinine } - \text { Pre-Dialysis Creatinine}}{\text {Post-Dialysis Urea Nitrogen } - \text { Pre Dialysis Urea Nitrogen}}

Distribution of Kt/V and URR measurements

As you’re probably aware, Kt/V is a measurement of a patient’s dialysis treatment efficiency that is based on their blood flow rate (BFR) and their urea clearance. URR is a measurement of dialysis treatment efficiency that takes into account both BFR and the amount of urea removed during the session.

\text {URR } = x / y

x = percent of removal of urea from plasma at the beginning of the dialysis session – 100% would mean complete removal

y = percent of removal at end of each exchange – 100% would mean complete removal

URR versus Kt/V

As you can see, there is a tight relationship between URR and Kt/V. If you have a high URR, it suggests that your patients are not retaining enough fluid to stay hydrated and may need to be given more IV medications to help them stay hydrated. On the other hand, if you have a low URR, then your patients are probably retaining too much fluid through their kidneys and possibly even getting water poisoning (hyponatremia).

In order to prevent these complications from occurring in your patients after surgery or during treatment for another disease state such as cancer or dialysis, it is important that we monitor both these factors regularly so we can adjust dosages accordingly based on what needs changing from one day to the next.

How to use the URR calculator

Our urea reduction ratio calculator uses a pretty simple formula. All you need to do is enter the pre-dialysis urea level and the post-dialysis urea level, and the calculator will give you the URR. Keep in mind, that when dealing with health-related calculators, you should always consult a medical professional before coming to any conclusions.


What is urea?

Urea is a waste product of protein metabolism that is produced by the liver and excreted in the urine.

How do you calculate the urea reduction ratio?

You can calculate the urea reduction ratio by subtracting the post-dialysis urea level from the pre-dialysis urea level.

What is the normal urea reduction ratio?

Usually, over 50% is a good result.