Isolated neutropenia

Last updated Nov. 2, 2025, 10:54 p.m. by ivo

Tags: Neutropenia

The neutrophil reference range will vary depending on the age, gender and pregnancy status of the patient, as well as the laboratory performing the test. In general, neutropenia is considered mild with a neutrophil count < 1.5 x10⁹/L; moderate if < 1 x 10⁹/L; and marked if < 0.5 x 10⁹/L.

Generally, the risk of infection is not significantly increased until the neutrophil count is < 0.5 x 10⁹/L.

Causes

• Persistent neutropenia may be due to a drug effect, and antipsychotics, anticonvulsants and antithyroid drugs are often implicated.
• Other common causes include viral infection or immune mediated phenomena.
• Occasionally, mild-moderate neutropenia may be idiopathic and, if isolated and uncomplicated by infection, does not require further investigation.
• Neutropenia can be seen in chronic liver disease with portal hypertension and hypersplenism.
• ‘Benign ethnic neutropenia’ is a well-recognised entity that occurs in 25-50% of people of African and Middle Eastern descent. It is typically associated with mild neutropenia, is uncomplicated and does not require treatment. Neutrophil counts as low as 0.7 x10⁹/L are normal in this condition. It is believed to have a genetic basis and is associated with the absence of Duffy group antigens on the patient’s red blood cells.
• Neutropenia related to bone marrow pathology tends to be progressive over time; and may be associated with changes in other cell lines, immature cells or dysplastic changes on the blood film, and hepatosplenomegaly or lymphadenopathy.

Evaluation

• Evaluation for infections including hepatitis B and C and HIV serology
• Signs and symptoms of autoimmune disease or inflammatory conditions
• Medications
• Blood film to assess for dysplastic features
• Following an initial finding of a mild neutropenia, it is reasonable to repeat the blood count in 4-6 weeks to assess progress.
• If the neutropenia persists, with no identified reactive cause, and no other associated cytopenias, observation, with full blood counts every 3-6 months is appropriate.

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When To Refer

Symptoms

• Unxplained fevers > 38° C
• Unintentional weight loss
• Night sweats

Physical examination

• Hepatosplenomegaly
• Lymphadenopathy

Laboratory

• Neutrophil count < 0.8 x 10⁹/L
• Anaemia (Hb < 100 g/L)
• Thrombocytopenia (PLT < 100x10⁹/L)
• Immature cells on peripheral blood film
• Dysplastic features on peripheral blood film
• Progressive lymphocytosis