Reactive (secondary):
- Infection
- Chronic inflammation
- Smoking
- Stress
- Obesity
- Drugs, for example:
- Corticosteroids
- Beta-agonists
- Lithium
- Epinephrine
- Endocrine disorders:
- Hypercortisolism
- Thyroid storm
- Pre-eclampsia
- Post-splenectomy state
- Bone marrow stimulation
- Nonhematologic malignancy
- Inherited disorders
Clonal (primary):
- Chronic neutrophilic leukemia
- Chronic myelogenous leukemia
- Essential thrombocytosis (ET)
- Polycythemia vera (PV)