Wearable Artificial Kidney (WAK) Explained


Nov 21, 2022

Wearable Artificial Kidney (WAK) Explained

Wearable Artificial Kidney (WAK) Explained

What is a WAK?

WAK stands for the Wearable Artificial Kidney and in the field of research and development of a wearable dialysis device, WAK is in the lead, and may be available to dialysis patients within a few years. Internationally known nephrologist and internist, Dr. Victor Gura is the creator of the WAK;  a miniature dialysis device designed to be worn by the patient 24 hours a day, 7 days a week.  A decade of research and over $30 million went into its development.  The WAK has been through several transformations to make it as light and comfortable as possible, and has been through three human trials, one in the United States and two in Europe, with a fourth trial to be conducted in early 2023.  

Dialysis Explained

Dialysis has been used to treat patients with end stage renal disease for nearly 80 years.  Over  the decades improvements have been made as medical science and technology have advanced.  However, a primary drawback is much the same today as it was in 1943 when Willem Johan Kolff built the first working dialyzer; the bulky, heavy machinery that normally requires a patient to have treatments done away from home in a clinic, hospital or dialysis center.  This impacts the patient's overall quality of life, requiring treatments that last several hours, three times per week, while following a restrictive diet and limiting fluid intake. 

Most patients with end stage renal disease receive dialysis treatments to compensate for some of their lost kidney function by removing excess fluids and waste from the blood.  However, dialysis is unable to replace the kidney's role in regulating metabolism, endocrine function, and maintaining blood pressure and electrolyte balance.   

A Better Way

The best treatment for end stage renal disease is a kidney transplant, however a shortage of donor kidneys means most people spend years on transplant waiting lists.  Dialysis treatments enable those patients to be on a waitlist for years, extending countless lives.  But researchers have sought to develop a wearable, artificial kidney that would allow patients with ESRD to receive dialysis as they go about their daily lives, and to provide patients with more frequent and longer dialysis sessions  in order to improve blood pressure control, weight, nutritional status, reduce stress on the heart, and clear the blood of toxins, wastes, and excess fluids at a slower rate that is closer to the continuous process that healthy kidneys are able to perform.  Also the time commitment traveling to a dialysis center for treatment that is lengthy, combined with a restrictive diet can have a negative impact on patients lives.  

A wearable, artificial kidney could allow patients to receive dialysis while going about daily lives . It could improve the removal of waste products and fluids through more frequent, longer, or continuous dialysis sessions.  This could improve a patient's health while also reducing the negative impact that treatment may have on a person's life. 

Conventional hemodialysis machines are heavy, they need to be connected to an electrical outlet, and use many liters of water in each treatment session.  Home dialysis equipment is meant to be portable, however the weight of the equipment, the need of an electrical connection, and the amount of dialysate required restrict a patients mobility for hours at a time. The out of pocket costs for home dialysis may also be a barrier for some patients.  There will be increased utility bills to consider, for water and electricity. Home dialysis may also place more demands and responsibilities on a patient's caregiver, impacting their quality of daily life.  

Likewise, dialysis performed at a clinic or center may have negative monetary consequences.  These may include travel expenses, and potential loss of employment due to the amount of time spent in treatment centers each week.  All of these reasons have led researchers to attempt to develop wearable artificial kidney since the early days of dialysis.  They have been limited by the technology available. Today there have been  developments in different fields that make a lightweight, wearable dialysis device possible.  

In Development

Currently there are five different Wearable Artificial Kidneys in development around the World; one is from the United States, others are Singapore, Italy, Netherlands, and Sweden. However only one of the devices has published results from trials in humans; the Wearable Artificial Kidney, or WAK from Blood Purification Technologies Inc.

The WAK is worn on a belt around the waist and weighs about 7 pounds.  It includes a miniature, battery- powered pump to power the flow of both blood and the dialysate, and additional micro pumps to control fluid removal, and the infusion of anticoagulants, and the delivery of other substances to the dialysate.  Safety mechanisms include a bubble detector and wetness sensors at the arterial and venous access sites to detect blood leaks.  The WAK requires only 400 ml of sterile water.


No wearable artificial kidney has yet received approval for marketing anywhere in the world. Although the WAK was accepted by the FDA (Food and Drug Administration) for the Expedited Access Pathway Program (EAP). This program is intended to improve clinical data collection and reduce the time to approval for innovative technologies that serve important clinical needs.  

The number of new cases of end-stage renal disease are increasing worldwide due to an aging population,  and increasing rates of Diabetes and Hypertension.  In the United States it is estimated that 40% to 60% of eligible patients, and particularly those already using home peritoneal dialysis and hemodialysis may choose to use a wearable artificial kidney; if they are found to be safe and if they are as effective as traditional dialysis therapy.  

Patients who participated in the trial studies of the WAK reported satisfaction with the device.  They reported more satisfaction with the WAK than with the conventional types of dialysis, especially in terms of convenience,  freedom, fit with their lifestyle, reduced treatment related side effects, and less discomfort during treatment.  

The WAK did experience some technical problems during the last human trials that they are currently working to remedy.  They found no serious adverse effects to patients during trials.  The projected cost of the WAK is currently not available, though the developer of the device has stated they believe the cost of the WAK and the monthly cost of disposable supplies will be less than those of current hemodialysis systems.  

Dialysis patients who use a wearable artificial kidney will still need to be monitored by healthcare professionals and to attend regular clinical visits for replacement of supplies and device maintenance, with frequency of those visits not yet known.  Also, similar to other types of home dialysis, patients, caregivers, and healthcare professionals will all need training on the use of the wearable artificial kidney.  

No information is available today about training, and there is not a projected date that the WAK will be available, although analysts are quite optimistic that the WAK will indeed be the first wearable artificial kidney to be marketed for sale to patients and that it will be in the very near future, approximately two to three years from now!      


Related Articles

What is Dialysis?

The Federal Government Improvement Plan for Dialysis Centers


National Center for Biotechnology Information


About the Author

Monica Thomas

Monica McCarthy has bachelors in Political Science and Criminal Justice from Central Washington University.  A majority of her career was spent as a political consultant.   She currently works at KidneyLuv as a staff writer.

Patient Education Disclaimer

This material is for informational purposes only. It does not replace the advice or counsel of a doctor or health care professional. KidneyLuv makes every effort to provide information that is accurate and timely, but makes no guarantee in this regard. You should consult with, and rely only on the advice of, your physician or health care professional.

KidneyLuv Logo