A simple test to check the capacity for eliminating an infused fat emulsion. Before starting the next infusion of fat, 5-6 hours after the previous infusion is terminated, a blood sample should be taken as for ESR (with citrate). The sample is centrifuged at 1200 - 1500 rpm. If the plasma is milky or markedly opalescent, it is a sign of lipemia and the planned infusion should be postponed. However, analysis of plasma triglycerides is recommended as the TG level may sometimes be high in spite of the clarity of the plasma.