Refer a patient with suspected anorexia nervosa immediately to a community-based, age-appropriate eating disorder service for assessment and management, without using a watchful waiting strategy NICE NG69.
Consider referral urgently if the patient is at risk of serious physical complications, such as severely compromised physical health, electrolyte imbalance, or rapid weight loss exceeding 1kg per week NICE CKS.
Refer if there is evidence of acute mental health risk, such as risk of suicide or serious self-harm, or if the patient has a lack of support at home that impedes recovery NICE CKS.
In cases where physical health is severely compromised or the patient cannot be safely managed in outpatient settings, urgent referral to specialist services is indicated NICE CKS.
Additionally, consider referral if the patient presents with complications like malnutrition, endocrine disturbances, or physical signs of deterioration, or if they are involved in activities at high risk of eating disorders (e.g., professional sport, dance) NICE NG69.