ACDIS tip: The difference between ANC and WBC count
By Sharme Brodie, RN, CCDS
I’ve been asked in several classes about the difference between an absolute neutrophil count (ANC) and white blood cell (WBC) count and whether they can both be used for evaluating pancytopenia. Let’s take a look at what each of these terms mean and what they represent.
The ANC is the number of neutrophils (also referred to as segs, segmented neutrophils, polys, and, in the most immature stage, bands or stabs). Neutrophils are a type of WBCs, and very important in fighting fungal and bacterial infections. A low neutrophil count is called neutropenia.
The ANC can be calculated by {(% of neutrophils + % of bands) divided by 100} x WBC count = ANC. An ANC count of less than 1,000 or lower is an indicator of a weakened immune system.
There are different types of WBCs (leukocytes) including lymphocytes, monocytes, neutrophils, eosinophils, and basophils, with the two most common being lymphocytes and neutrophils. A low WBC count is called leukopenia. Pancytopenia is a condition in which a person's body has too few red blood cells (anemia), WBC leukopenia, and platelets (also known as thrombocytopenia).
Leukopenia is often caused by a decrease in neutrophils, so some use the terms “leukopenia” and “neutropenia” interchangeably. It is possible, however, for a patient to have a WBC count within normal range, while their neutrophil count is low. But because neutrophils normally make up the largest part of the total WBC count, the WBC count is usually low when the neutrophil count is low.
Pancytopenia starts because of a problem with the bone marrow, the spongy tissue inside of the bones, where the cells are produced, this can be caused by a variety of conditions including disease or exposure to certain chemicals or drugs.
Editor’s Note: Brodie is a CDI education specialist and CDI Boot Camp instructor for HCPro in Middleton, Massachusetts. For information, contact her at sbrodie@hcpro.com. For information regarding CDI Boot Camps, click here.