Dr Choong has been a practising gastroenterologist in the Hills area since 2003. Within a short period of time he has built a practice that has engendered the trust of the GPs in the area. 

Dr Choong was staff specialist and director of Emergency Unit position at Hornsby Hospital from 2003 to 2013.. He is involved in clinical teaching for medical students from Sydney University.

Dr Choong has many years of experience in general gastroenterology and diagnostic gastroscopy and colonoscopy including polypectomy and emergency endoscopic intervention.