Clinical Studies of Total Body Nitrogen in an Australian Hospital

The first reports of the measurement of Total Body Nitrogen (TBN) by In Vivo Neutron Activation Analysis (IVNAA) using a cyclotron date from the early 1970’s (Harvey et al., 1973). By the late 1970’s other laboratories were using the prompt gamma IVNAA technique with isotopic neutron sources (Mernagh et al., 1977; Vartsky et al., 1979a). The prompt IVNAA method is a relatively simple, non-invasive test which requires approximately 20 minutes of the patient’s time. The radiation dose is minimal, and both capital and running costs are small. Clinically, Total Body Protein (TBPr) can be reliably estimated from TBN (TBPr = 6.25 × TBN). The many clinical applications of the technique are described by Wahlqvist and Marks elsewhere in this volume, and by McNeill (1988). It is therefore surprising that so few hospitals are currently using the technique.