[Subjective nutrition assessment: Part 1 - A review of its validity after two decades of use]

The subjective global assessment is a clinical method for nutritional assessment that considers not only body composition alterations but also changes in physiological function. The method is simple, inexpensive and non-invasive, and it can be performed at bedside, and its use was described for the first time almost two decades ago.

To review the validity studies of subjective global assessment described in literature in the last two decades of its use.

It was performed a systematic review in MEDLINE, using "subjective global assessment" as search term and the most relevant papers were selected.

Being a subjective method, its precision depends on the observer's experience. Nevertheless, the method showed a good diagnostic precision when performed by trained observers. Subjective global assessment was validated by convergent validity, when this method was compared to other objective nutritional assessment methods, and by predictive validity, showing that subjective global assessment could identify patients who were at high risk for developing postoperative complications.

Subjective global assessment has been a good option in nutritional assessment in surgical patients and some modifications have been suggested to adjust the method to other clinical situations. The observer experience is of extreme importance, since the precision of the method depends on it.