Objective: To define reference hematologic and biochemical lab values in older individuals.
Design: Randomly selected, age- and gender-stratified participants.
Setting: Visits by participants to four research clinics.
Patients: A total of 5201 participants in the Cardiovascular Health Study, an observational study of older Medicare-eligible individuals living at home.
Measurement: Information about health status, previous illness, and medication use was obtained from participants and/or their MDs. This information was used to define a healthy subset of the population. Blood samples were obtained for Cholesterol, HDL and LDL cholesterol, fasting and 2-hour postload glucose and insulin, fibrinogen, factors VII and VIII, potassium, creatinine, albumin, uric acid, white blood count, hematocrit, hemoglobin, and platelet count.
Results: Significant differences were found for age group and/or gender for all mean values. Many tests were significantly different from the generally accepted reference ranges used in clinical laboratories.
Conclusions: In some situations accepted laboratory norms for the general population can not be extrapolated to older adults. There are implications for both research and clinical practice.