Consider referring a patient with IBS for further investigation or specialist review if they present with 'red flag' indicators such as signs and symptoms of cancer, inflammatory markers for inflammatory bowel disease, or if symptoms are persistent, severe, or worsening despite initial management NICE CG61.
Specifically, refer if there are persistent or worsening symptoms, or if the patient develops new concerns such as marked distress, feeding difficulties, or faltering growth in infants, or if there is persistent, frequent regurgitation beyond the first year of life NICE NG1.
Additionally, if initial dietary and lifestyle advice, including dietary modifications and symptom management, are ineffective after review within two months, consider referral to a specialist dietitian or secondary care for further assessment and management NICE CKS.