How to calculate absolute neutrophil count

Absolute neutrophil count (ANC) is the full variety of neutrophils within the white blood cell (WBC) count. This is often a part of an entire blood count (CBC) with a differential. Although some laboratories calculate ANC for us, it will be significant to know what’s included within the calculation because this number is commonly used to evaluate the danger of infection and aid in cancer treatment.

Please keep in mind that neutrophils are essentially the most common kind of white blood cells and so they conduct the immune response. A decrease in neutrophil counts normally implies that the patient is at increased risk of infection.

ANC may be calculated by multiplying the full white blood cell count by the proportion of neutrophils and dividing by 100 (Coates, 2019). Sometimes on a lab report chances are you’ll see a percentage of neutrophils known as polymorphonuclear cells (PMN), in addition to young neutrophils (also called bands). In this case, add the proportion of neutrophils (PMN) and the proportion of bands (and divide by 100) before multiplying by the WBC.

Let’s try an example.

If the white blood cell count is 6.3k/uL, the neutrophil count is 56.1%, and the bands are 3%, what’s the ANC?
ANC = WBC (cells/uL) x [percent (PMNs + bands) ÷ 100]

ANC = 6300 cells/uL x [(56.1%+3%) ÷ 100]

ANC = 6300 cells/uL x (59.1% ÷ 100)
ANC = 6300 cells/µl x 0.591
ANC = 3720 cells/µl

What does it mean?

As we mentioned, ANC is an indicator of infection risk. Neutropenia (decrease in neutrophil count) is often defined as an ANC of lower than 1,500 cells/µl in an adult and may be classified as mild, moderate and severe.

Example No. 2

JD is a 42-year-old man who suffers from progressive fatigue. Physical examination reveals splenomegaly and lymphadenopathy. His CBC results with a difference are:

White blood cells 1.2 THO/uL
Hemoglobin 10.7 g/dl
Hematocrit 31%
Platelets 262 THO/µl
% Neutrophils 70.1%
% Lymphocytes 30.8%
% Monocytes 9.5%
% Eosinophils 2.4%
% Basophils 1.2%
% Teams 3%

Based on these results, let’s calculate JD’s ANC.

ANC = WBC (cells/uL) x [percent (PMNs + bands) ÷ 100]

ANC = 1200 cells/uL x [(70.1%+3%) ÷ 100]

ANC = 1200 cells/uL x (73.1% ÷ 100)
ANC = 1200 cells/µl x 0.731
ANC = 877.2 cells/µl

JD has moderate neutropenia and would require further evaluation to find the cause.

Neutropenia could also be detected during evaluation of other signs and symptoms, as in JD, or as an incidental finding on a routine blood count. In each cases, further evaluation is needed to find out the underlying pathology and potential medical emergencies. You must also bear in mind that the majority patients undergoing chemotherapy will experience their ANC, or nadir, inside five to 10 days after completing their chemotherapy session.

Berliner, N. (2020, February 21). Management of an adult with unexplained neutropenia. https://www.uptodate.com/contents/approach-to-the-adult-with-unexplained-neutropenia

Coates, T. D. (2020, April 15). Laboratory evaluation of neutrophilic disorders. https://www.uptodate.com/contents/laboratory-evaluation-of-neutrophil-disorders