The crucial role of Kidney Exchange Programmes and the ENCKEP and KEP-SOFT innovations making it possible


Kidney Exchange Programmes (KEPs) play a vital role in saving lives, providing a critical lifeline for patients suffering from end-stage renal disease. Without them, patients often face limited options for a successful transplant. However, establishing these programs is complex and challenging.

COST Action European Network for Collaboration on Kidney Exchange Programmes (ENCKEP), along with its innovative spin-off COST Innovators Grant (CIG) Software for Transnational Kidney Exchange Programmes (KEP-SOFT), have helped to address the challenges KEPs face in terms of prioritisation, equity, and accessibility. Prof. David Manlove, Chair of ENCKEP and KEP-SOFT and Professor of Algorithms and Complexity at the School of Computing Science at the University of Glasgow, sheds light on how KEPs function, policies and practices across Europe, challenges KEPs face, and how the achievements of ENCKEP and KEP-SOFT will increase opportunities for recipients waiting for a kidney.

Photo of a bag of blood in a gloved hand ready for a transfusion

Kidney Exchange Programs for better survival prospects for kidney patients.

Kidney Exchange Programs (KEPs) work by enabling patients with incompatible donors to swap with others in the same predicament. Swapping helps increase donations and reduces the time patients spend on waiting lists. A single non-directed donor might trigger a chain of transplants that benefit multiple recipients. And studies have shown that living-donor transplants boost patient survival to 90% after ten years, compared with an average of 75% amongst deceased-donor transplants. The average life expectancy for patients on dialysis currently stands at five to ten years*.

KEPs prioritise hard-to-match patients and excel at finding flexibility around difficult constraints. However, recipients must provide a living donor willing to participate altruistically, as financial incentives are not allowed.

ENCKEP and KEP-SOFT Cycles Chains: a two-way exchange, a three-way exchange, and an altruistic donor chain
From left to right: a two-way exchange, a three-way exchange, and an altruistic donor chain. 
Image credit: Radu Stefan Mincu

Challenges of KEPs

Setting up KEPs is difficult due to the ethical, legal, practical, and logistical considerations that must be faced. These include ratifying policy decisions, establishing a software infrastructure, and satisfying clinical requirements. Additionally, KEPs vary across European countries in terms of policy, clinical practice, and optimisation methods. For instance, the maximum number of recipients allowed to exchange donors in a single “cycle” differs between the Netherlands and the UK. Furthermore, some countries allow non-directed donation while others prohibit it. Crossmatching** processes also vary. The ENCKEP and KEP-SOFT network has proved instrumental in meeting many of these challenges. And its associated software addresses many of these variations.

ENCKEP and KEP-SOFT Compatibility graph
Compatibility graph illustrates a typical structure to find an optimal set of cycles and chains that form kidney exchanges.
Here, an optimal solution is illustrated by red and turquoise circles (corresponding to donors and recipients) that appear at the outer edges of the compatibility graph. 
Image credit: David Manlove, produced using software written by Tommy Muggleton.
*What is kidney dialysis?
**What is crossmatching?

COST ENKEP and KEP-SOFT solutions

The major outcomes of the COST Action ENCKEP and its spin-off, KEP-SOFT, are significant” explains David Manlove. “ENCKEP built up a collaborative and multidisciplinary network involving directors of transplantation organizations, policy makers, clinicians, ethical and legal experts, computer scientists, mathematicians, and economists.

ENCKEP  workshop Tallinn 2017
ENCKEP workshop in Tallinn 2017

For example, in February 2018 an ENCKEP workshop was held at IKEM (the Institute of Clinical and Experimental Medicine) in Prague where participants were able to observe a live nephrectomy followed by a live transplant carried out via video link from the operating theatre. “It was an incredible experience!” says David.

“Being part of the ENCKEP and KEP-SOFT projects meant that I had access to a multidisciplinary network that helped advance publications and impact, which simply would not have been possible without COST funding.”

Professor David Manlove, Chair of ENCKEP COST Action and the KEP-SOFT COST Innovators Grant

ENCKEP and KEP-SOFT shared best practices relating to KEPs in Europe. The Actions published a range of articles along the way, thereby laying the foundations for the creation of new KEPs throughout the continent. KEP-SOFT developed flexible and comprehensive software that balances varying constraints and optimisation objectives across a variety of KEPs. This solution provides functionality for registering clinical data relating to recipients and donors, virtual crossmatching via the analysis of antigens of donors and of recipients, and ultimately discovers optimal solutions for matching.

The KEP-SOFT software also helps with low- and high-resolution antigen matching, and enables international collaboration across countries. Thereby it increasing living kidney donation opportunities. The software’s capabilities can benefit highly sensitised and minority-ethnic-background patients, and reduce both wait times and financial burdens for healthcare organizations.

The University of Glasgow has ensured that the KEP-SOFT software will be available to transplantation organisations. It also plans to spin-off the relevant pieces into a non-profit social-enterprise company: Kepsoft Community. This company will provide products and services to the European transplant community, including the marketing, distribution, maintenance, development and customisation of the KEP-SOFT software.

KEP-SOFT collaborates with companies, including SMEs, as part of the Action. This ensures transparency and the best available opportunities for kidney patients in Europe. In addition, ENCKEP influenced the development of the ScandiaTransplant kidney paired Exchange Programme (STEP).

On 15 June 2023, EU4Health will publish a call for proposals to implement an EU-wide KEP. On page 65, the announcement makes specific reference to the KEP-SOFT software. This presents an exciting potential future opportunity to influence further developments in KEPs in the European context and to widen the user-base of the KEP-SOFT software.


The ENCKEP and KEP-SOFT networks have made significant strides in advancing the field of kidney exchange, bringing together experts from multiple disciplines to develop innovative solutions and best practices.

Additional information

ENCKEP network website

KEP-SOFT website

Ouputs from ENCKEP: