Constipation in adults can usually be managed in primary care. However, referral is indicated when:

• Cancer is suspected.
• Referral for colonoscopy should be considered in people over 50 years of age if 'red flags' are present.
• An underlying cause is suspected.
• If an underlying problem is suspected, consider having the results from blood tests for inflammatory markers, hypothyroidism, hypercalcaemia, and coeliac disease available before the person attends their appointment.
• Pain and bleeding on defecation (e.g. from an anal fissure) is severe or does not respond to treatment for constipation.
• Consider consider surgical referral.
• Treatment is unsuccessful.
• Treatment failure may be early, when attempts at relieving faecal loading fail, or late, if there is difficulty maintaining remission.
• Management may require further tests (such as blood tests, radiological imaging for bowel studies, or consideration of rectal suction biopsy, or transit studies).
• Assessment is required prior to referral for other interventions (such as psychology, psychiatry).
• Faecal incontinence is present.
• Referral to Continence Service (if available) may be appropriate for advice and monitoring.
• More detailed support with diet is required.
• Consider dietetics referral.

These recommendations are largely pragmatic, although they also include referral guidelines for suspected cancer published by the National Institute for Health and Clinical Excellence (NICE) [NICE, 2005].