Comparison of methods to categorize undernutrition in children.

We compared the results of three methods of categorizing undernutrition in a group of 258 children referred for evaluation of "failure to thrive." There was broad variation between the number of children classified as malnourished (75% to 98%) and the degree of undernutrition, depending on the method used. We recommend that categorization systems be used only to define a child as having a risk of possible adverse effects of undernutrition, not as being malnourished.