In persistent moderate neutropenia, without an infection or drug related cause, testing might include ANA (anti-nuclear antibodies), B12, folate, SPE (serum protein electrophoresis), HIV, liver enzymes, Hepatitis B and rheumatoid factor. Look for changes on physical examination.
NEUTROPHILIA (HIGH NEUTROPHIL COUNT)
Neutrophils - High
Most likely cause
Infection/inflammation
Necrosis
Any stressor/heavy exercise
Drugs
Pregnancy
Smoking
CML
Red flags
Person particularly unwell
Severity of neutrophilia
Rate of change of neutrophilia
Presence of left shift
Neutrophils are the primary white blood cells that respond to a bacterial infection. The most common cause of marked neutrophilia is a bacterial infection.
Neutrophils react within an hour of tissue injury and are the hallmark of acute inflammation. An excessive increase in neutrophils (>50 x 109/L) as a reactive phenomenon is known as a leukaemoid reaction.
Neutrophils generally exhibit characteristic changes in response to infection. The neutrophils tend to be more immature, as they are being released earlier. This is called a left shift (Figure 2). In a severe infection the neutrophils may show toxic granulation and other toxic changes such as vacuolation and the presence of Döhle bodies.
Neutrophils will frequently be increased in any acute inflammation, therefore will often be raised after a heart attack, or other infarct and necrosis. Any stressor, from heavy exercise to cigarette smoking, can elevate the neutrophil count.
Figure 2: Diagram of left shift.
A number of drugs have been demonstrated to increase the neutrophil count, including steroids, lithium, clozapine and adrenalin. Even nervousness may very slightly raise the neutrophil count because of the effect of steroid release.
Pregnancy is associated with a slight increase in total neutrophil count demonstrating a left shift. Most laboratories provide pregnancy specific reference ranges.
Persistent elevation of neutrophils may be a sign of chronic myeloid leukaemia (CML). Characteristic changes are a moderate increase in neutrophil count (usually >50 x 109/L), with a left shift and a prominence of myelocytes. Basophilia and/or eosinophilia may also be present. Chronic mild neutrophilia without left shift is very unlikely to be due to CML.
CML occurs in all age groups but most commonly in the middle aged and elderly. The annual incidence is estimated at 1 - 2 cases per 100,000.
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