1. Patients with isolated diabetes should be tested if they have:
a. Diabetes diagnosed young (≤35 years in White Europeans and ≤30 years in high prevalence ethnic groups).
AND
b. Unlikely to have Type 1 diabetes because:
They are not on insulin treatment.
OR
They are on insulin treatment with all autoantibodies tested negative (minimum testing of GADA and IA2A) and a random non-fasting C peptide value ≥200pmol/l
AND
c. Have features suggestive of MODY:
An HbA1c at diagnosis of diabetes <7.5% (58mmol/mol), if diagnosed under 18 years of age, OR BMI <30kg/m2 adult (child BMI <95th centile) and a parent with diabetes (if White) or BMI <27kg/m2 (child BMI <95th centile) and a parent with diabetes (if high prevalence type 2 diabetes ethnic group). OR Have a MODY probability score ≥20% if not insulin treated and ≥10% if insulin treated (see https://www.diabetesgenes.org/exeter-diabetes-app/ModyCalculator) 2. Syndromic diabetes: Patients with diabetes AND non-autoimmune extra-pancreatic features • Diabetes diagnosed young AND • Unlikely to have type 1 diabetes (see 1b) or type 2 diabetes. AND • Non-autoimmune extra pancreatic features suggestive of syndromic monogenic diabetes e.g. • Cystic renal disease and/or congenital anomaly of kidney or urinary tract • Bilateral sensorineural deafness • Developmental delay • Developmental defects • Cardiomyopathy • Optic atrophy • Microcephaly 3. Diabetes with severe insulin resistance • Patients have features of severe insulin resistance in the absence of obesity: • Acanthosis nigricans OR • A fasting insulin >150pmol/l if not insulin treated OR if insulin treated an insulin requirement >3U/kg/day
AND
• Diabetes that is unlikely to be type 1 diabetes (see 1.0 above) or type 2
diabetes (BMI<30kg/m2 if white (<95th in children) or BMI <27kg/m2 (<95th in children) if high prevalence type 2 diabetes group).

1. Patients with isolated diabetes should be tested if they have:
a. Diabetes diagnosed young (≤35 years in White Europeans and ≤30 years in high prevalence ethnic groups).
AND
b. Unlikely to have Type 1 diabetes because:
They are not on insulin treatment.
OR
They are on insulin treatment with all autoantibodies tested negative (minimum testing of GADA and IA2A) and a random non-fasting C peptide value ≥200pmol/l
AND
c. Have features suggestive of MODY:
An HbA1c at diagnosis of diabetes <7.5% (58mmol/mol), if diagnosed under 18 years of age, OR BMI <30kg/m2 adult (child BMI <95th centile) and a parent with diabetes (if White) or BMI <27kg/m2 (child BMI <95th centile) and a parent with diabetes (if high prevalence type 2 diabetes ethnic group). OR Have a MODY probability score ≥20% if not insulin treated and ≥10% if insulin treated (see https://www.diabetesgenes.org/exeter-diabetes-app/ModyCalculator) 2. Syndromic diabetes: Patients with diabetes AND non-autoimmune extra-pancreatic features • Diabetes diagnosed young AND • Unlikely to have type 1 diabetes (see 1b) or type 2 diabetes. AND • Non-autoimmune extra pancreatic features suggestive of syndromic monogenic diabetes e.g. • Cystic renal disease and/or congenital anomaly of kidney or urinary tract • Bilateral sensorineural deafness • Developmental delay • Developmental defects • Cardiomyopathy • Optic atrophy • Microcephaly 3. Diabetes with severe insulin resistance • Patients have features of severe insulin resistance in the absence of obesity: • Acanthosis nigricans OR • A fasting insulin >150pmol/l if not insulin treated OR if insulin treated an insulin requirement >3U/kg/day
AND
• Diabetes that is unlikely to be type 1 diabetes (see 1.0 above) or type 2
diabetes (BMI<30kg/m2 if white (<95th in children) or BMI <27kg/m2 (<95th in children) if high prevalence type 2 diabetes group).