A previously well 52‐year‐old man was seen with a 3‐week history of hyperglycaemic symptoms. He had a BMI of 40.8 kg/m2, with no evidence of eruptive xanthomas. His random blood glucose was 19.0 mmol/l (reference range 3.5–6.9 mmol/l), with an HbA1c concentration of 128 (28–42) mmol/mol [13.9 (4.7–6.0)%]. A venous blood sample was reported as being ‘turbid’, with a serum triglyceride level of 128.4 (0.5–1.7) mmol/l. His visual acuity was normal.