Urea reduction ratio

Urea Reduction Ratio

The Urea Reduction Ratio (URR) is a measure used in the field of nephrology to assess the effectiveness of dialysis treatment in patients with chronic kidney disease. It is a simple and widely used method to evaluate how well urea, a waste product, is removed from the blood during a dialysis session.

Calculation

The URR is calculated using the following formula:

URR = ((Upre - Upost) / Upre) _ 100

where Upre is the concentration of urea in the blood before dialysis, and Upost is the concentration of urea in the blood after dialysis. The result is expressed as a percentage, indicating the proportion of urea removed during the treatment.

Clinical Significance

A higher URR indicates more effective removal of urea, which is associated with better patient outcomes. The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines recommend a minimum URR of 65% for adequate dialysis.

Comparison with Kt/V

The URR is often compared with another measure of dialysis adequacy, Kt/V. While both metrics assess the removal of urea, Kt/V is considered more comprehensive as it accounts for the volume of distribution of urea in the body. However, URR remains popular due to its simplicity and ease of calculation.

Limitations

Despite its usefulness, the URR has limitations. It does not account for the removal of other toxins or the patient's residual kidney function. Additionally, it does not consider the duration of dialysis or the patient's body size, which can affect the interpretation of results.

Related Pages

• Dialysis
• Chronic kidney disease
• Kt/V
• Nephrology

External Links

• KDOQI Guidelines

File:Urr ktv.svg

Diagram comparing URR and Kt/V