Age-related changes in laboratory values used in the diagnosis of anemia and iron deficiency.

Laboratory results from the Second National Health and Nutrition Examination Survey (NHANES II) were used to define age-related changes in laboratory values that are related to the diagnosis of anemia and iron deficiency. Analyses included Hb, hematocrit, red blood cell count, red cell indices, iron, total iron-binding capacity, transferrin saturation, and erythrocyte protoporphyrin. Computation of median values and 95% ranges by age and sex for each laboratory test were performed on 15,093 subjects between 1 and 74 yr of age who had complete laboratory data on venous blood, after excluding those subjects with an abnormality in one or more of three other laboratory tests. Age-related changes in laboratory measurements, such as those described herein, must be taken into consideration in order to optimize the identification of individuals with anemia and iron deficiency.