Because many laboratory values change with age, the study of healthy aging as well as diagnosis of disease in geriatric patients requires specific age-corrected reference intervals. We have established such reference intervals for a healthy population aged 65-74 years by selection of a sample group applying the clinical criteria of the SENIEUR protocol and we have compared them with those of a young control group (20-33 years) fulfilling the same criteria. Significant or minor elevations were seen, e.g. for plasma concentrations of fasting glucose, urea, total and LDL-cholesterol, triglycerides, gamma-glutamyl-transferase, alkaline phosphatase, erythrocyte sedimentation rate and serum neopterin levels. These reference intervals can be used for selecting a SENIEUR compatible population aged between 65 and 74 years. Additionally, plasma lipid parameters (cholesterol, triglycerides) are proposed to be included in the SENIEUR protocol.