A/Prof Thong completed his advance specialty training in rheumatology and clinical immunology/allergy at Tan Tock Seng Hospital, Singapore in 2002. This was followed by a clinical fellowship in paediatric and adult clinical immunology/allergy at the University of Southampton and Southampton General Hospital, United Kingdom from 2002-2003. He is presently Senior Consultant in the Department of Rheumatology, Allergy and Immunology, and from 1 April 2024, Chairman Medical Board at Tan Tock Seng Hospital. He is also Adjunct Associate Professor at the Lee Kong Chian School of Medicine, Nanyang Technological University Singapore.