Normal values for peripheral blood white cell counts in women of four different ethnic origins.

Total and differential white cell counts were studied in 399 women living in the same community in Britain but drawn from four different ethnic groups. The groups were white (northern European), Indian, black (African and West Indian), and Oriental. The total white cell count and absolute neutrophil count were significantly lower in the black group than in each of the other groups. The absolute monocyte count was higher in whites than in each of the other groups. Contrary to earlier reports, the absolute eosinophil count in blacks was no higher than in whites, suggesting that the high eosinophil counts previously found had an environmental rather than a genetic cause. The eosinophil count of Indians was only marginally higher than that of whites and the difference was not significant, again suggesting that high eosinophil counts previously reported had an environmental cause. No ethnic variation was found in the absolute lymphocyte count. The lower white cell count and neutrophil count found in blacks is of considerable practical importance, and blacks should not be assessed in relation to reference ranges derived for whites. Nevertheless, the eosinophil count in healthy blacks is no higher than that of whites and counts above reference ranges for whites should be considered clinically important. The differences between white cell counts of Indians and Orientals and those of whites are minor and for practical purposes they can be assessed in relation to reference ranges derived for whites.