A 17 year old female comes to you with abdominal pain and intermittent diarrhoea for the last 8 weeks. She is under stress due to studies and attributed her symptoms to this. On further questioning she admits to blood in her stool recently and increasing frequency of stools per day up to 3 times a day. She admits to malaise but has not developed any fever. There is no weight loss. There is no history of recent travel locally or abroad. The rest of her family are well. She is haemodynamically stable.
Based on this history you suspect Inflammatory Bowel Disease, so which faecal investigation is needed to reach a diagnosis?