Age- and sex-related blood cell values in healthy black Americans.

Hemoglobin, mean corpuscular volume, erythrocyte count, and leukocyte count were measured, and hematocrit, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were computed electronically for 7,739 healthy black persons. The study population comprised 3,393 males and 4,346 females 1-84 years of age, all from the Washington, DC, metropolitan area. Persons with sickle cell disease and elevated hemoglobin F were excluded from analysis, but those with traits for hemoglobin S, C, and thalassemia were not. Mean and percentile values are presented in tabular form. Hemoglobin, hematocrit, and mean corpuscular volumes were lower than those reported in surveys of white populations. Beginning with the 11-15-year age groups, black males had higher red cell values than black females. After age 30, mean hemoglobin levels for men gradually declined, while those in women rose, so that the sex difference diminished after 60 years of age. Leukocyte counts were higher in young children and in women, compared with men ages 21-50 years. After 60 years of age, the sex difference disappeared. Further large surveys that exclude data on persons with iron deficiency are needed in black populations.