Benign Leukocytosis: This condition is characterized by a persistent, mild elevation in white blood cell (WBC) count without any underlying disease or infection. It can be seen in healthy individuals and may be related to genetic factors, stress, or other non-pathological conditions.

Chronic Infections: Low-grade, chronic infections such as dental infections, sinusitis, or urinary tract infections can cause a mild, persistent elevation in WBC count. These infections may not always present with overt symptoms.
Inflammatory Conditions: Conditions like rheumatoid arthritis, lupus, or other autoimmune diseases can lead to chronic inflammation, which may result in an elevated WBC count.
Medication-Induced Leukocytosis: Certain medications, including corticosteroids, lithium, and beta-adrenergic agonists, can increase WBC count as a side effect.

Chronic Myeloid Leukemia (CML): Although less likely, CML can present with a mild elevation in WBC count and may be asymptomatic for a long period. Missing this diagnosis could lead to delayed treatment and poor outcomes.
Lymphoproliferative Disorders: Conditions like lymphocytic leukemia or lymphoma can also present with an elevated WBC count and may be asymptomatic in early stages.
Parasitic Infections: Certain parasitic infections, such as toxoplasmosis or hookworm infection, can cause a mild, persistent elevation in WBC count.

Myeloproliferative Neoplasms: Other myeloproliferative neoplasms like essential thrombocythemia, polycythemia vera, or primary myelofibrosis can occasionally present with an elevated WBC count.
Congenital Disorders: Rare congenital disorders affecting the bone marrow or immune system can lead to persistent leukocytosis.
Other Rare Infections: Certain rare infections, such as brucellosis or tuberculosis, can cause a chronic elevation in WBC count, although these would typically be accompanied by other symptoms or risk factors.