Absolute Neutrophils Low (Neutropenia)

A low absolute neutrophil count (ANC) is called neutropenia. Neutrophils are the white blood cells that act as the body's first line of defence against infection, so when there are too few of them, infections become more likely and can become serious quickly.

Get medical help straight away if your neutrophils are low, or you are having chemotherapy, and you have a temperature of 38°C (100.4°F) or higher for more than an hour, or a single reading of 38.3°C (101°F) or higher. Do not wait to see if it settles.

What counts as low?

An ANC below 1,500 cells per microlitre (1.5 × 10⁹/L) is neutropenia. It is usually graded as:

Once the count is below 1,500, infections become more common. A normal adult ANC is about 1,500 to 8,000 cells/µL, although each lab sets its own range. See ANC normal range and how segs and bands make up the ANC.

Some people have a lifelong, naturally low count linked to the Duffy-null blood type (Duffy antigen null neutropenia, formerly called benign ethnic neutropenia). It does not increase the risk of infection, but doctors only reach this conclusion after ruling out other causes.

Common causes

• Chemotherapy and radiotherapy. After chemotherapy the count often falls lowest between 7 and 12 days after a treatment, although this varies.
• Viral infections, such as flu, and severe bacterial infection (sepsis).
• Medicines other than chemotherapy.
• Bone marrow problems, such as aplastic anaemia or bone marrow failure.
• Low vitamin levels that cause megaloblastic anaemia.
• Autoimmune disease and an enlarged, overactive spleen (hypersplenism).

Symptoms

Neutropenia itself often causes no symptoms. It is usually found on a blood test. The warning signs are those of an infection:

• fever
• chills and sweats
• shortness of breath
• a stiff neck
• burning or pain when passing urine

Because a low count can let even a minor infection become serious quickly, these signs need prompt attention.

Treatment

Treatment depends on the cause and how low the count is. Your doctor may treat an underlying cause, change a medicine, or adjust the timing of further treatment. Fever with a low neutrophil count in someone having cancer treatment (febrile neutropenia) is treated as an emergency in hospital.

Lowering the risk of infection

If your count is low, the CDC recommends that you:

• clean your hands often
• avoid crowds and people who are ill
• do not share food, cups, cutlery or toothbrushes
• cook meat and eggs all the way through, and wash raw fruit and vegetables carefully
• avoid touching pet urine or faeces; wear gloves and wash your hands afterwards
• wear gloves for gardening
• shower or bathe daily and clean your teeth with a soft toothbrush
• get the seasonal flu vaccine