*Note about medical information:*

This information is presented for informational purposes only and is intended for professionals. While we strive to provide accurate information, this information might be outdated, unintentionally misleading or incorrect. Consult a medical professional and/or read the primary sources cited in our article before basing any decision on this information.

Neutropenia is a **reduced number of neutrophil granulocytes in the blood**. Normally, one would expect a number \geq 1500\ \frac{\text{neutrophils}}{\mu l} in the peripheral blood, with a typical value of 2500-4500 \frac{\text{neutrophils}}{\mu l}.

The decreased number of neutrophils is associated with reduced immune response and hence causes an increased chance of infection. Patients with neutropenia have a risk of developing **febrile neutropenia** (also known as **neutropenic sepsis**). Febrile neutropenia is a **medical emergency** and hence **requires immediate treatment**!

Neutropenia can be easily diagnosed using a *complete blood count* to count the number of neutrophils in the peripheral blood. In case a lab report does not contain the *absolute neutrophil count (ANC), *you can also multiply the *percentage of neutrophils* with the *leukocyte count*.

The different grades of neutropenia are defined in the **Common Terminology Criteria for Adverse Events (CTCAE).** On this page, we use *Version 5.0 published in 2017.*

**Grade 1 neutropenia**

is defined as an **absolute neutrophil count (ANC) **of

\leq 1500\ \frac{\text{neutrophils}}{\mu l} or equivalently

\leq 1500\ \frac{\text{neutrophils}}{mm³} or equivalently

\leq 1.5\ billion\ \frac{\text{neutrophils}}{l} or equivalently

\leq 1.5e9\ \frac{\text{neutrophils}}{l}

**Grade 2 neutropenia**

is defined as an **absolute neutrophil count (ANC) **of

1000\dotsb 1500\ \frac{\text{neutrophils}}{\mu l} or equivalently

1000\dotsb 1500\ \frac{\text{neutrophils}}{mm³} or equivalently

1000\ billion\ \dotsb 1500\ billion\ \frac{\text{neutrophils}}{l} or equivalently

1e9\dotsb 1.5e9\ \frac{\text{neutrophils}}{l}

**Grade 3 neutropenia**

is defined as an **absolute neutrophil count (ANC) **of

500\dotsb 1000\ \frac{\text{neutrophils}}{\mu l} or equivalently

500\dotsb 1000\ \frac{\text{neutrophils}}{mm³} or equivalently

500\ billion\ \dotsb 1000\ billion\ \frac{\text{neutrophils}}{l} or equivalently

0.5e9\dotsb 1e9\ \frac{\text{neutrophils}}{l}

**Grade 4 neutropenia**

is defined as an **absolute neutrophil count (ANC) **of

\leq 500\ \frac{\text{neutrophils}}{\mu l} or equivalently

\leq 500\ \frac{\text{neutrophils}}{mm³} or equivalently

\leq 500\ million\ \frac{\text{neutrophils}}{l} or equivalently

\leq 0.5e9\ \frac{\text{neutrophils}}{l}

**Grade 5 neutropenia**

is defined as death (like all *Grade 5 adverse events*).