Saturday, February 9, 2008

Neutrophil Counts for Age and Race

Here's what the Hematology of Infancy and Childhood (5th Edition) says about the neutrophils counts for age and race:

Quite interesting, and contrary to other texts-- it also contradicts what it says later in this same textbook. I think this is because several people wrote this book and it wasn't proofed against the other authors (make sense?) ANYHOW here's what it says:

"Neutropenia is defined as an absolute decrease in the number of circulating neutrophils in the blood. Normal neutrophil levels should be stratified for age, race and other factors. For whites, the lower limit for neutrophil counts (neutrophils and bands) is 1000 cells/ul in infants between 2 weeks and 1 year of age. After infancy, the corresponding value is 1500 cells/ul Blacks have somewhat lower neutrophil counts, and the lower limits of normal can tentatively be considered from 200 to 600 cells/uL less relative to whites. The basis
for this observation is probably due to a relative decrease of neutrophils in the bone marrow storage compartment. Note that falsely low white blood cell counts can result when counts are done long after blood is drawn or after excessive leukocyte clumping in the presence of certain paraproteins."