Nutrition support is recognized as an important cofactor in altering morbidity and mortality of hospitalized patients. Paramount in delivering proper nutrition support is the accurate determination of baseline metabolic and nutritional status, thus influencing necessary protein requirements. After nutritional intervention, routine laboratory monitoring is used to measure the efficacy and to reassess metabolic stress level. Accurate determination of nitrogen excretion (and nitrogen balance) remains the standard in prescribing and monitoring the protein and nutritional treatment regimen. This article examines nitrogen excretion determinations in the clinical setting, including proper collection techniques, laboratory measurements, and analyses and their effect upon nitrogen balance studies.
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