A meta-analysis of IBD prediction models based on lower GI symptoms in pediatric patients highlighted that the addition of blood tests (CRP, ESR, Hb, platelets, and albumin) to a symptom-based model improves the model performance in a hospital setting.39 It also highlighted that most of the studies evaluating the performance of the addition of blood or stool test to symptom-based models were based on secondary care data (referred patients), and none were based in primary care. Here, GSTM1 is linked to inflammatory bowel disease.