Dr Ratnayake is a Consultant Microbiologist in the Department of Laboratory Medicine and Pathology His special clinical interests include molecular diagnostics, antimicrobial stewardship, as well as infection prevention and control.

Dr Ratnayake obtained his primary medical qualification from the University of Colombo, Sri Lanka in 2005. He underwent postgraduate training in Medical Microbiology and Virology in the United Kingdom and entered the Specialist Register in General Medical Council, UK in 2013. He worked as a Consultant Microbiologist in the National Health Service, UK from 2013 to 2017.He moved to Singapore in 2017 where he worked at Ng Teng Fong General Hospital until he joined Woodlands Health in 2021 where he has been involved in planning laboratory services. He serves in a number of hospital and national committees involved in controlling the spread of infections and emergence of antimicrobial resistance in Singapore.

As a Microbiologist, Dr Ratnayake provides a consultancy service to various clinical colleagues in all aspects of prevention, diagnosis, and treatment of infections. He strives to provide a high-quality Microbiology service to patients while minimising unnecessary laboratory investigations and inappropriate antibiotic use which can adversely affect safety and quality of patient care.