[Reference values for hematologic laboratory tests and hematologic disorders in the aged]

Abstract

The establishment of reference values in the complete blood count and lymphocyte subsets for the aged is necessary for diagnosis and therapy since the number of the aged is increasing rapidly in recent years. However, it is problematical to define the healthy aged because of physiological changes with aging, compared with the healthy adults. Red blood cell count, hemoglobin concentration(Hb) and hematocrit for the healthy aged showed the tendency of moderate decreasing with aging. These phenomena become more obvious by dividing the healthy aged into three groups, 65-74 years, 75-84 years and over 85 years. The mean corpuscular volume(MCV) for the healthy aged showed the tendency of increasing with aging, while mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration for the healthy aged showed no tendency with aging. No changes for the healthy aged were observed in the leukocyte differential, white blood cell count and platelet count with aging. Results of lymphocyte subsets(CD3, CD4, CD8, CD19 and CD4/CD8 ratio) for the healthy aged are not coincident among reporters at present because the healthy aged population is different and the determination of lymphocyte subsets is not standardized. It is important to diagnose as anemia below Hb 11.0 g/dL between 65 and 74 years, Hb 10.0 g/dL over 75 years using Hb level with high accuracy. Most of hematologic disorders in the aged are the secondary anemia based on malignant tumor. In the aged between MCV 95 and 120 fL or over MCV 120 fL, myelodysplastic syndrome or vitamin B12 deficiency is considered, respectively. In the future, more vertical study in the aged population is needed to establish the reference values for the aged.