American Journal of Clinical Nutrition, Vol 50, 1219-1230, Copyright © 1989 by The American Society for Nutrition

Clinical chemistry reference intervals for healthy elderly subjects

¹ From the University of New Mexico School of Medicine, Departments of Pathology and Family, Community, and Emergency Medicine

In 1979, 304 healthy elderly individuals in New Mexico were recruited for a longitudinal study of nutrition and aging. Repeat measurements on a yearly basis of commonly requested clinical chemistry analytes allowed the calculation of reference intervals, between and within-subject variance components, and percentiles for change in concentration between two yearly measurements. The latter was further divided into analytical and biological variance components. The upper 95th percentile for the difference between two yearly measurements, expressed as a percent of the population mean, ranged from 4% for Na⁺ to 20% for total cholesterol and to > 90% for ferritin. Year-to-year differences attributable to the biological component ranged from a low of 2% of the population mean for Na⁺ to 70% for gamma-glutamyltransferase.

Key Words: Elderly • reference intervals • clinical chemistry