EDITOR, - Alan M Garber and Andrew L Avins state that use of the triglyceride concentration to guide lipid lowering treatment “must still be seen as experimental.”1 I suggest that measurement of fasting plasma triglyceride concentrations should be mandatory in any patient with hypercholesterolaemia, particularly if lipid lowering treatment (either diet or drugs) is contemplated. The type of diet or drug to which a patient responds best depends on the relative amounts of circulating cholesterol and triglyceride. Moreover, patients with very high triglyceride concentrations (almost all of whom will have hypercholesterolaemia) should be identified and treated appropriately. They are at risk of pancreatitis, and neither the hypercholesterolaemia nor the hypertriglyceridaemia is likely to respond to …