TTR and nutritional deficiency disease: The levels of serum protein levels such as TTR are often maintained in a chronic malnourished state (such as anorexia nervosa), and are decreased in well-nourished individuals who have experienced a recent stress or trauma.2,15–17 The question has been raised whether, instead of reflecting overall nutritional status, low serum TTR should be regarded as a bio-marker of increased risk of malnutrition, requiring further nutritional assessment.