Estimation of urinary nitrogen losses from urea excretion in patients with intestinal diseases requiring parenteral nutrition, and in those with hepatic decompensation.

A comparison of daily urinary nitrogen excretion measured directly, with values derived from urea excretion, was carried out on 110 occasions in patients with either gastrointestinal disease requiring total parenteral nutrition or with alcoholic liver disease. The values were found to correlate well in both patient groups (r = 0.88 and 0.9 respectively). Values of urinary nitrogen loss calculated from urea excretion may safely be used when performing nitrogen balance studies in such cases.