The Board

Executive Directors

Lorin Gresser

Chief Executive Officer
Lorin founded Dem Dx in 2015 after graduating from medical school and has been the CEO of Dem Dx ever since. As well as her medical degree from King's College London she has a MA in Natural Sciences from Cambridge University and an MBA from Harvard University.

Steve Varley

Chief Technical Officer
Steve has over 30 years experience in open systems software design, including 10+ years in mobile app development. Steve holds a BA in Computing Science from Teesside University.

Non-executive Directors

DemDx- Karen Bach headshot black and white – fixed

Karen Bach

Chair of the Board
Karen joined Dem Dx as Chair in 2021. She brings 30 years of experience in growing, international businesses with a focus on scale-ups particularly in health tech and media tech. Karen joined Dem Dx because she is blown away by the diagnostics tool and the productivity it delivers to resource-constrained health care organisations.
Tracy Sambrook black and white – fixed 2,jpg

Tracy Sambrook

Tracy joined DemDx as an NED in 2021. She brings 20 years of finance experience, scaling and raising funding for growth-stage businesses across the tech sector. Tracy joined Dem Dx because of Dem Dx's capability to deliver significant and much needed transformation to frontline healthcare, offering an opportunity to improve healthcare delivery in both developed and developing healthcare environments.
Michael Steel

Michael Steel

Following a successful career in strategy consulting, Michael founded Greenbrook Healthcare in 2006 and grew it to become the largest provider of NHS urgent treatment centres in the country. In 2019, the Greenbrook business was successfully sold to Totally plc with £40m+ turnover, 700+ staff and a reputation for high quality and safe service provision. Michael holds an MBA from INSEAD and an MPhil. in Economics from Oxford University.
Sally Johnson (Headshot) b+w

Sally Johnson

Sally is a practicing GP with 30 years experience in the NHS. Alongside her clinical roles she has worked as the Chief Medical Officer of NHS and International Private primary and urgent care organisations. She has expertise in developing and delivering high quality, innovative and safe services. Her interests include pathway innovation, clinical governance, telemedicine, regulatory compliance and workforce development. As well as supporting Dem Dx Sally is a practicing GP, CQC inspector and Medical Examiner.

The Board