Kt/V Calculator Daugirdas
Table of contents
What does Kt/ V stand for in dialysis?What is normal Kt/ V?Difference between Kt/ V and URRHow to calculate Kt/ V in dialysis?FAQsThe Kt V calculator allows you to assess your patient's dialysis or peritoneal dialysis efficacy and adequacy, using both Urea Reduction Ratio (URR) and the Daugirdas Kt/ V formula.
A short read below will acknowledge you with the basic definitions used in dialysis evaluation and the Kt measurements. We'll also explain the complicated maths that stands behind our simple tool. ⏳
What does Kt/ V stand for in dialysis?
The Kt/ V in dialysis is used for the measurement of the dialysis efficacy. It describes the rate of removal of the excessive fluids/substances (K) in a given treatment (t) of a given patient (V). This index is probably the most popular system to assess the dialysis dose.
The abbreviation itself stands for:
 K – dialyzer clearance – blood passage
 t – duration of dialysis in minutes
 V – volume of body water
This value is dimensionless  is not based on any unit and cannot be calculated using its separate parts and their units.
The Kt/ V system, however, may disadvantage women and smaller people and result in worse dialysis results in these groups of patients  this difference is caused by the variances of their body water content.
Want to know more? How about checking our other kidneyrelated tools, such as GFR calculator and Urine output calculator?
What is normal Kt/ V?

The dialysis is considered efficient when Kt/V is greater or equal to 1.2. That's the minimum value that must be kept at all times. All the values that fall below that range are a sign of the flawed process of hemodialysis therapy.

The peritoneal dialysis target Kt/V is equal to 1.7 weekly (according to the International Society of Peritoneal Dialysis).
However, the patient's treatment should be adjusted to the Kt/V values of more than the recommended target!
It's a precaution used to ensure that the process is indeed of appropriate quality  it's crucial since this variable is directly related to the patient's future outcomes and is correlated to survival!
💡 Current guidelines recommend the weekly Kt/V in Acute Kidney Injury to be at least 3.9
The Kt/ V calculator displays your results along with its basic efficacy evaluation.
Our tool requires you to know three fundamental lab findings:
 Kt/ V urea  both pre and post dialysis level of urea
 Volume of removed ultrafiltrate
You may read some more about these values using FEUrea calculator and BUN/ creatinine ratio calculator.
Difference between Kt/ V and URR
Kt/ V is considered to be of a better value and more accurate than the URR.
Why is Kt/V better?
Even that both of these values are closely related, the Kt/ V system takes into account two additional variables:
 Urea removed with the fluid during the dialysis
 Urea produced by the body during dialysis
The measurement of fluid removed during dialysis using the Kt/ V is also essential because the excessive amount of fluids accumulated in the patients' bodies might cause inevitable harm to their cardiovascular system.
The
recommends the Kt/V to be the primary measure of adequacy.How to calculate Kt/ V in dialysis?
Our standard Kt/ V calculator uses the following equation:
Kt/V = ln((Post BUN/Pre BUN) 0.03) + (4  3.5 × (Post BUN/Pre BUN)) × (UF/Weight)
Where:

Post BUN means the level of postdialysis Blood Urea Nitrogen, given in milligrams per deciliter (mg/dL).

Pre BUN means the level of predialysis Blood Urea Nitrogen, given in milligrams per deciliter (mg/dL).

UF stands for the volume of removed ultrafiltrate, given in liters (L).

Weight stands for the postdialysis weight of a subject, given in kilograms (kg).

ln stands for the logarithm with the base of e → the natural logarithm.
Remember: all multiplications and divisions have a priority over adding and subtractions and should always be calculated first.
How do I determine if the Kt/V value is normal?
To determine if a Kt/V value is normal, consider the following guidelines:
 An effective treatment typically requires a minimum Kt/V value of 1.2 or higher for hemodialysis patients.
 Peritoneal dialysis patients should aim for a weekly Kt/V value of 1.7.
 In cases of acute kidney injury, a weekly Kt/V of at least 3.9 is recommended as a minimum standard.
What is the Kt/V value if the postdialysis BUN is 20?
The Kt/V value is 1.03 if the postdialysis BUN is 20 mg/dL, assuming that:
 The predialysis BUN is 50 mg/dL;
 The duration of dialysis was 2 hours;
 The ultrafiltration volume is 2 liters; and
 The postdialysis weight is 70 kg.
What does a Kt/V value of 1.07 mean in hemodialysis therapy?
The Kt/V value of 1.07 in hemodialysis therapy may indicate that the treatment may not reach the desired effectiveness level. Note that the interpretation of Kt/V values can vary depending on the patient's condition and treatment goals.
What is the difference between single pool Kt/V and Kt/V?
Singlepool Kt/V is mainly used for assessing thriceweekly hemodialysis, while standardized Kt/V can be used to estimate clearance for dialysis at any frequency. If you want to determine your patient's dialysis or peritoneal dialysis efficacy and adequacy, use the Omni Kt/V calculator.