What is Absolute Neutrophil Count (ANC)?

From the Guidelines

The Absolute Neutrophil Count (ANC) is a measure of the number of neutrophils in the blood, expressed as cells per microliter (cells/μL) or cells per cubic millimeter (cells/mm³), and is crucial for assessing infection risk and guiding treatment decisions in patients with neutropenia or those at risk of developing it 1.

Definition and Calculation

The ANC is calculated by multiplying the total white blood cell count by the percentage of neutrophils, including both mature neutrophils (segs) and immature forms (bands).

• A normal ANC typically ranges from 1,500 to 8,000 cells/μL in adults.
• An ANC below 1,500 cells/μL is considered neutropenia, with severe neutropenia defined as an ANC below 500 cells/μL, which significantly increases infection risk.

Clinical Significance

The ANC is vital for monitoring patients undergoing chemotherapy, those with certain blood disorders, or those taking medications that can suppress bone marrow function.

• When the ANC falls below 1,000 cells/μL, physicians often recommend infection precautions.
• Prophylactic antibiotics may be considered when the ANC drops below 500 cells/μL.

Guidelines for Management

According to recent guidelines, hematopoietic growth factors such as granulocyte-colony-stimulating factor (G-CSF) should be used judiciously, considering the risk of febrile neutropenia and the potential for adverse effects 1.

• The use of G-CSF is recommended for primary prophylaxis of febrile neutropenia in patients with a high risk of infection, typically when the risk exceeds 20% 1.
• Regular monitoring of the ANC helps healthcare providers assess infection risk and make appropriate treatment decisions, prioritizing the patient's morbidity, mortality, and quality of life.

From the FDA Drug Label

Consider dose escalation in increments of 5 mcg/kg for each chemotherapy cycle‚ according to the duration and severity of the absolute neutrophil count (ANC) nadir. Recommend stopping NEUPOGEN if the ANC increases beyond 10‚000/mm3 Table 1 Recommended Dosage Adjustments During Neutrophil Recovery in Patients with Cancer Following BMT Absolute Neutrophil CountNEUPOGEN Dosage Adjustment

• If ANC decreases to less than 1,000/mm3 at any time during the 5 mcg/kg/day administration‚ increase NEUPOGEN to 10 mcg/kg/day‚ and then follow the above steps
• When ANC greater than 1,000/mm3 for 3 consecutive daysReduce to 5 mcg/kg/day
• Then, if ANC remains greater than 1,000/mm3 for 3 more consecutive daysDiscontinue NEUPOGEN
• Then, if ANC decreases to less than 1,000/mm3Resume at 5 mcg/kg/day

Absolute Neutrophil Count (ANC) is the number of neutrophil cells in a person's blood, which is an important indicator of the body's ability to fight infection.

• ANC is calculated by multiplying the total number of white blood cells (WBC) by the percentage of neutrophils in the blood.
• In the context of NEUPOGEN therapy, ANC is used to monitor the effectiveness of treatment and adjust the dosage accordingly.
• The goal of NEUPOGEN therapy is to increase the ANC to a level that reduces the risk of infection and other complications associated with neutropenia.
• The ANC values mentioned in the drug label, such as 1,000/mm3 and 10,000/mm3, are used as thresholds to guide dosage adjustments and treatment decisions 2.

From the Research

Definition of Absolute Neutrophil Count (ANC)

• Absolute Neutrophil Count (ANC) is defined as the number of neutrophils in the blood, with a normal range typically considered to be above 1.5 × 10(9)/L 3.
• Neutropenia is characterized by an ANC of less than 1.5 × 10(9)/L, and can be caused by a variety of factors, including congenital disorders, infections, and bone marrow suppression 3.

Clinical Significance of ANC

• ANC is an important indicator of the body's ability to fight infection, and low ANC levels can increase the risk of bacterial and fungal infections 4.
• ANC is often used in conjunction with other laboratory tests, such as complete blood cell counts (CBCs) and bone marrow examinations, to diagnose and manage conditions such as neutropenia and leukemia 3.

Diagnostic Value of ANC

• ANC has been shown to be a sensitive indicator of bacterial infections, particularly in adults 4.
• However, in certain populations, such as infants and the elderly, band count may be a more sensitive indicator of bacterial infections than ANC 4.
• Morphologic changes in neutrophils, such as toxic granulation, vacuolation, and Dohle bodies, can also be useful in predicting bacterial infections 4.