As CLL progresses excess lymphocytes in the bone marrow compromise the production of other blood cells. Chemotherapy aimed at reducing lymphocytes also reduces other blood cell counts.
One of the cell types that is important for CLL patients to monitor is neutrophils. Neutrophils are a type of white blood cell and are an important defense against infection, especially bacterial infection. Neutrophils are also referred to as granulocytes, polys, bands, PMNs, segs, and nonsegs. When neutrophil counts become too low (neutropenia), patients are at risk of infection.
Normal neutrophil counts are between 2,000 and 8,000 (2.0 to 8.0) per microliter of blood. Many laboratories will also report this as 2.0 - 8.0 x 10.09/L. The numbers 2.0 - 8.0 remain the same but have been adjusted to reflect the larger volume of blood. Experience has shown that neutrophil counts above 2.0 will keep almost everyone safe from infections. Patients with counts between 2.0 and 1.0 should take precautions such as staying away from crowds, children with runny noses, etc. Between 1.0 and .5, patients are in jeopardy of infections from everyday bacteria found in salads, fresh unpeeled fruit, shellfish, rarely cooked foods, etc. Below .5 most physicians consider that patients already have infections, usually from their own bacteria, in the gastrointestinal tract, nose, etc. (see also: What is a neutropenic diet?).
When neutrophil counts fall too low because of advancing disease and/or chemotherapy, physicians may administer granulocyte colony-stimulating factors (G-CSF) to boost neutrophil counts. G-CSF is also known as filgrastrim or by its trade name Neupogen™.
If neutrophil counts are reported as percentages, patients can calculate absolute neutrophil counts (ANC) by multiplying the total white blood count by the percentage of neutrophils. While percentage reports are considered adequate for most patients, absolute values are more important for patients with blood (hematologic) disorders.