Ruey-Leng graduated from the University of Bradford and completed her pre-registration training at the GlaxoWellcome (currently known as GlaxoSmithKline) and Southend General Hospital. Once qualified, she worked as a hospital pharmacist for several years before she decided to undertake a PhD in Biological Chemistry at the Imperial College London. Upon completion of her PhD, she held a postdoctoral research position there for a year. Her research has focused on the application of metabolic profiling methods (metabonomics) to a large-scale international epidemiological study based on multivariate statistical method development and implementation. Ruey-Leng joined Medway School of Pharmacy (MSoP) as a Clinical Lecturer in Pharmacy Practice in October 2009. She also holds an Honorary Clinical Lectureship in the Imperial College London Section of Biomolecular Medicine (awarded 2009). Ruey-Leng is a member of the Clinical and Professional Practice group and Renal and Cardiovascular Physiology and Pharmacology research group.

Ruey-Leng has experience in characterising the human metabolome using spectroscopic methods, such as Nuclear Magnetic Resonance and Mass Spectrometry together with chemometric modeling techniques (metabonomics) and its applications. Her research focuses on discovery of metabolic biomarkers of cardiovascular, diabetes and renal diseases with a focus on personalised healthcare in human population studies, and emphasising the effects of diet and physical activities on health in general. More recently, she has extended her research in the development of chemometric and statistical methods for analysis of ‘omics’ data and biomarker recovery. Ruey-Leng together with Professor Jeremy Everett and Professor Frank Pullen, have recently formed a Medway Metabonomics Research Group (MMRG). The main purpose of the MMRG is to develop and strengthen metabonomics and pharmacometabonomics capabilities in this region. Pharmacometabonomics is a new branch of metabonomics that is concerned with the prediction of the effects of drugs on a person or animal, based on an analysis of their pre-dose metabolic profile. It is predicted to have much future importance for personalised medicine.