What criteria should I use to determine whether to refer a patient wit

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Criteria for referral of a patient with hyperglycaemia to a specialist include:

Suspected or confirmed diagnosis of type 1 diabetes, especially in adults presenting with ketosis, rapid weight loss, age under 50 years, BMI below 25 kg/m2, or personal/family history of autoimmune disease, or if diagnosis is uncertain and requires specialist assessment .
Children and young people with suspected type 1 diabetes should be referred immediately (same day) to a multidisciplinary paediatric diabetes team for confirmation and immediate care .
Patients with an HbA1c level of 48 mmol/mol (6.5%) or above indicating type 2 diabetes should be referred for further care .
Adults with type 2 diabetes who have hyperglycaemic emergencies such as diabetic ketoacidosis (DKA) or hyperosmolar hyperglycaemic state (HHS), or suspected acute kidney injury that cannot be managed in primary care, require immediate hospital admission or specialist referral .
Consider urgent specialist advice or referral if the underlying cause of hyperglycaemia is unclear, if the patient is dehydrated or at risk of dehydration, if vomiting persists beyond 2 hours, or if the patient and carers are unable to maintain blood glucose above 3.5 mmol/L or are exhausted .
Patients requiring insulin titration and adjustment should have this managed by healthcare professionals with relevant expertise, implying referral to specialist diabetes services if primary care expertise is insufficient ,,.

What criteria should I use to determine whether to refer a patient with hyperglycaemia to a specialist?