53 Nutritional support may range from simple dietary advice to long-term total parenteral nutrition (TPN). In between is a whole spectrum of clinical conditions and appropriate forms of nutritional support (Fig 53.1). As we move to the right, climbing the scale of severity of disease, we increase the level of support and in so doing increase the need for laboratory back-up. The clinical biochemistry laboratory plays an important role in the diagnosis of some disorders that require specific nutritional intervention, e.g. diabetes mellitus, iron deficiency anaemia and hyperlipidaemia, but a much greater role is played in the monitoring of patients receiving the different forms of nutritional support.
Nutritional support