Low neutrophils: causes and when to worry

Low neutrophils often come from a virus you just had or from a medicine. Many people of African descent, and some of Middle Eastern descent, naturally have lower counts, with no harm. The number to look at is the absolute count, and how low it is.

What low neutrophils mean

With few neutrophils, your body has fewer defences ready against bacteria. When the absolute count is below your report’s limit, it is called neutropenia.

The lower it goes, the more it matters. Just below the limit, the risk of infection usually changes little. Below 0.5 x10⁹/L the risk of serious infections grows: see a doctor the same day. If you also have a fever, call 112 or go to the emergency department.

What causes low neutrophils

The first is the most common. The last two are rare.

Symptoms

Usually none. You cannot feel low neutrophils: they are found on a blood test.

When they are very low you get ill more often, with fevers, mouth ulcers, a sore throat or skin infections that heal slowly.

With low neutrophils, take a fever seriously: see a doctor the same day. If your absolute count is below 0.5, call 112 or go to the emergency department.

Low neutrophils with a normal white count

It can happen: your total white count is normal, but your absolute neutrophil count is low. The reverse happens too, with a low total and normal neutrophils.

Usually, though, the two go together: neutrophils are the largest share of your white cells, so when they drop, the total drops too. That is why you look at the NEU# line, not just the total or the percentage.

Which tests to read alongside them

These tests help find the cause.

What to do if they are low

How low they are and how you feel matter most. Where to start:

When to worry

Talk to your doctor if:

With Rosa, neutrophils below 0.5 x10⁹/L (absolute count) are always flagged to a doctor, urgently.

Frequently asked questions

What are the levels of neutropenia? It is usually called neutropenia when the absolute count is below your report’s limit. It is mild if it stays above 1, moderate between 0.5 and 1, and severe below 0.5 (in x10⁹/L). Below 0.5, see a doctor the same day, and with a fever call 112 or go to the emergency department.

Low neutrophils: should I worry? Usually not, if they are just below the limit, you feel well and the rest of your blood count is normal. A virus you just had is often behind it. Show the report to your doctor, who decides whether to repeat the test.

Can you have naturally low neutrophils? Yes. Many people of African descent, and some of Middle Eastern descent, have counts below the usual report limits because of a common genetic variant, with no higher risk of infection. A doctor can tell from your history, from tests repeated over time and, if needed, from a test for that variant.

Can low neutrophils mean a bone marrow problem? Rarely. In that case haemoglobin or platelets are usually low too, and the count does not recover. If so, your doctor asks for more tests.

How can I raise my neutrophils? It depends on the cause. After a virus they usually recover on their own. If vitamin B12 is short or a medicine is involved, your doctor decides what to do.

How often should they be checked again? If you feel well, with your usual checks: Rosa measures them twice a year. If they are low, follow your doctor’s timing.

Sources