Of the handful of types of white blood cells we have in our bodies, as many as 70 percent are known as neutrophils. For that reason alone we know that they're going to serve an important role, and the role they serve is to help the immune system fight infections.
Neutropenia, therefore, is defined as an abnormally low count of neutrophils in the bloodstream. While the exact amount can sometimes differ from one practice to another, for the purpose of this entry we will take the amount described by the National Comprehensive Cancer Network in its clinical practice guideline in oncology regarding the prevention and treatment of cancer-related infections.
According to those guidelines, neutropenia is defined as:
< 500 neutrophils / mcL
or
< 1,000 neutrophils / mcL and a predicted decline to < 500 mcL over the next 48 hours.
This definition is in accord with the current recommendations of the Infectious Diseases Society of America as well.
Neutropenia, when accompanied by a fever (known as febrile neutropenia) is considered an oncologic emergency because the patient is susceptible to a host of opportunistic and potentially fatal infections, and they require immediate medical attention.
Sources and further reading
- Boyiadzis, Michael M. et al. Hematology-Oncology Therapy. 2007. New York: McGraw Hill, Medical Publishing Division.
- National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology: Prevention and Treatment of Cancer-Related Infections.
- Mayo Clinic, Neutropenia
