TTR and nutritional deficiency disease: Zhang et al19 systematically evaluated studies on the application of blood biochemical indicators to the diagnosis of malnutrition in elderly patients, including 111 studies and 52 911 patients, and found that serum albumin, cholesterol, hemoglobin, and prealbumin measurements were directly related to a diagnosis of malnutrition, and that these measurements were reduced in the malnutrition group.