Analyses of laboratory data and establishment of reference values and intervals for healthy elderly people

Protein-energy malnutrition is a common disorder in the elderly. Although serum albumin is commonly used as a nutritional marker, data is lacking on serum albumin levels in the elderly. The purpose of this study was to determine whether serum albumin levels decrease with advancing age and to establish reference value and interval of laboratory data for elderly people (75 years and over). Blood samples from 13821 healthy people, 42064 outpatients, and 15959 inpatients were collected during 2008. Blood from 127 of our nutrition support team (NST) patients was also collected during August 2006 and May 2009, and analyzed. Serum albumin, hemoglobin, total cholesterol levels and lymphocyte count were determined. We analyzed the change in each parameter in accordance with age, compared the data for elderly people with younger people, and established new reference values. Clinical outcomes were examined depending on the improved reference values. Albumin was lower in older persons than in younger persons. The estimated reference value and interval were 42 (48-36) g/l in older persons and was much lower in NST patients. Hemoglobin was decreased while cholesterol and lymphocyte count were not changed in older persons: all were markedly decreased in NST patients. Terms of hospital stay were significantly longer and mortality rates were significantly higher in older persons, comparing from above to below using a new reference value of albumin (36 g/l). The serum albumin level decreases with advancing age, but it was maintained to some extent in healthy older people. Serum albumin levels related to the clinical outcome. Hemoglobin and cholesterol levels and lymphocyte count were all lower in NST patients. These measurements may be valuable markers of nutritional status and can help in guiding the need for nutritional support.