Advances in the causes of disorders of lipid metabolism, and effective intervention in atherosclerosis with medication, have increased the reliance on laboratory investigation in clinical practice. The conventional lipid profile, comprising fasting triglyceride, total cholesterol, high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) cholesterol, suffices for screening persons at risk of atherosclerosis. Additionally, lipoprotein (a) measurement enhances risk assessment and could explain atherosclerosis with a desirable lipid profile. Certain rare disorders in sterol and fatty acid metabolism do not alter the conventional lipid profile. Non-fasting samples are gaining popularity, as the triglycerides, although mildly increased, signify atherogenic lipoprotein remnant accumulation. Apoprotein A1 (apo A1) and apo B concentrations parallel HDL cholesterol and LDL cholesterol, respectively, and are of value in disorders of these lipoproteins. In severe dyslipoproteinaemia, special investigations establish the cause of the disease and may allow selection of better treatment. In such cases, not only apoprotein concentrations, but also enzyme or cell function, as well as genetic investigations, are relevant. The most important genetic disorders to recognise are familial hypercholesterolaemia, dysbetalipoproteinaemia and chylomicronaemia. Expertise in lipidology is limited in South Africa, but specialist centres can provide clinical and laboratory support to ensure best management of severe disorders.