Biomarkers

Low Neutrophils on a CBC: What a Low ANC Means and When to Worry

A low neutrophil result on a routine CBC is common and often mild. Learn how to read the Neutrophils % and Absolute Neutrophils (ANC) lines, the usual causes, including a lifelong Duffy-null pattern, and which patterns need prompt follow-up.

Published

September 24, 2026

Read time

12 min read

Medically reviewed by

Rhonda Collins, FNP-C

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Neutrophils are the most common white blood cells and the body’s first responders to bacterial infection. A low neutrophil result on a routine complete blood count (CBC) is usually mild, and the most common reasons are temporary, such as a recent viral infection or a medicine, or harmless, such as the lifelong lower count many people of African or Middle Eastern ancestry have. [1] [2] The line to read is Absolute Neutrophils (also printed as ANC or “Neutrophils (Absolute)”), not the percentage. A mildly low ANC with an otherwise normal blood count and no symptoms is typically confirmed with a repeat test rather than treated as urgent. A low count together with a fever is different, and needs prompt care.

Should you worry about low neutrophils?

Usually not, when the drop is mild, the rest of the CBC is normal, and you feel well. Three questions sort most results:

• How low is the absolute count? Adults are generally described as neutropenic below 1,500 neutrophils per microliter, and a count between 1,000 and 1,500 is classed as mild. [3]
• What did the rest of the report do? A low neutrophil count on its own reads differently from a low count next to anemia, low platelets, or other abnormal lines. [1]
• Is it new, or has it always looked like this? Older CBCs are one of the most useful pieces of information. A count that has sat at the same mildly low level for years is a different finding from one that has just dropped. [1]

The patterns that need prompt attention are a low count with fever, a count that keeps falling, a count in the moderate or severe range, or a low count alongside other abnormal blood counts. Those are covered in when a low count needs follow-up below.

Neutrophils % vs Absolute Neutrophils (ANC) on your report

A CBC with differential reports neutrophils in two ways, and they can disagree.

• Neutrophils % is the share of your white blood cells that are neutrophils.
• Absolute Neutrophils, also printed as ANC, Neutrophils (Absolute), or “Neutrophils #,” is the actual number of neutrophils, usually in thousands of cells per microliter (x10³/µL), which is numerically the same as x10⁹/L.

The absolute count is the total white blood cell count multiplied by the neutrophil percentage. [4] For example, a white count of 4.0 x10³/µL with 40% neutrophils gives an ANC of 1.6 x10³/µL, or 1,600 cells per microliter.

Clinicians read the absolute count because neutropenia is defined by it. [3] The percentage depends on every other white cell type. If your lymphocytes are high after a cold, your neutrophil percentage can drop even while the number of neutrophils stays normal. A low percentage with a normal ANC is usually not a neutrophil problem at all. For the percentage line on its own, see the neutrophil percentage reference, and for the absolute count, the neutrophils reference.

Mild, moderate, and severe low neutrophils

Start with the reference interval printed beside your result. That is your lab’s range, and it is the one that applies to your report.

Clinical references grade a low absolute neutrophil count in adults this way: [3] [1]

These categories describe how low a count is, not what caused it. Lab reference intervals do not always line up with them. One hospital’s standard ANC range, for example, started at 1,920 cells per microliter, so a result between about 1,500 and 1,900 can be flagged low on a report while sitting above the clinical definition of neutropenia. [5] The grading matters because infection risk rises as the count falls. [1]

Common causes of low neutrophils on routine labs

Most low neutrophil results found on routine blood work have an everyday explanation.

A recent viral infection

Viral infections are the most common infectious cause of a temporary drop. Examples include influenza, RSV, SARS-CoV-2, Epstein-Barr virus (mononucleosis), cytomegalovirus, hepatitis viruses, and HIV. [1] The drop is usually mild to moderate, starts with the illness, and resolves within days to a couple of weeks. [1] A CBC drawn during or just after a cold or flu can therefore catch a count that is already on its way back.

Medications

Many medicines can lower neutrophils, including some antibiotics, antithyroid drugs, anticonvulsants, the antipsychotic clozapine, and chemotherapy. [1] An unexpected drug reaction often appears one to six months after starting the medicine, and counts usually recover within one to three weeks after it is stopped. [1] Deciding whether a medicine is responsible, and whether to stop it, is a decision for the prescribing clinician. [3]

Vitamin B12, folate, or copper deficiency

The bone marrow needs vitamin B12, folate, and copper to make blood cells, and a deficiency of any of them is a recognized cause of low neutrophils. [3] These deficiencies tend to affect more than one cell line, so they are checked especially when red cells or platelets are also low. [1]

Autoimmune conditions

In autoimmune neutropenia the immune system removes neutrophils faster than normal. It can occur on its own or alongside conditions such as lupus and rheumatoid arthritis. [3] [1]

Duffy-null associated neutrophil count (formerly benign ethnic neutropenia)

Many people have a lower neutrophil count their whole lives because of an inherited blood type called Duffy-null. This is now called Duffy-null associated neutrophil count (DANC); older reports and articles call it benign ethnic neutropenia. [2]

• Who has it. About two in three people who identify as Black in the U.S. are expected to have the Duffy-null phenotype, and it is also found in people with Arabian Peninsula ancestry. [2]
• What it looks like. A lifelong, stable ANC that is often 1,000 to 1,500 cells per microliter and sometimes lower. [1]
• What it means. People with the Duffy-null phenotype have no increased risk of infection, but they are often labeled as having neutropenia. [2] [6]

The standard ranges printed on most reports were not built for this group. In a study of healthy Duffy-null adults, the central 95% range of ANC was 1,210 to 5,390 cells per microliter, compared with 1,920 to 7,600 for the hospital’s standard range. [5] Family physician guidance advises against an extensive workup in healthy people without symptoms who have a chronic mild low count associated with the Duffy-null phenotype. [3] If your ANC has always been mildly low and you do not get unusual infections, this is one of the most likely explanations. A Duffy blood group test can confirm it. [2]

When a low neutrophil count needs follow-up

A mildly low, stable count with no symptoms is the common, reassuring pattern. The features that change the picture are:

• a count in the moderate or severe range, or one that keeps falling on repeat tests;
• other abnormal counts on the same report, such as anemia or low platelets;
• an abnormal blood smear, or swollen lymph nodes or an enlarged spleen;
• a low count that stays low without a likely explanation.

These are the findings that lead clinicians to look further, sometimes as far as a bone marrow test. [1] If any of them applies to you, book a visit with your doctor and bring your earlier CBCs.

Low neutrophils and fever

Fever with a low neutrophil count needs prompt care. With a severely low count (below 500), a fever of 101°F or higher, or 100.4°F or higher for an hour, is treated as a medical emergency. [3] If you have a fever and know your count is low, contact your doctor that day, and go to an emergency department if your count is severely low or you feel very unwell.

The cancer and bone marrow question

Many people who see a low neutrophil flag wonder about leukemia or another bone marrow problem. Cancers that affect the bone marrow, such as leukemia, lymphoma, and myeloma, can lower neutrophils, and so can chemotherapy. [6] Those are not the usual explanation for a mildly low count on routine labs. Bone marrow testing is reserved for a count that is severe or persistently low without a clear cause, one that comes with other low blood counts, or an abnormal smear. [1] For a mildly low count in an otherwise healthy person, the first steps are a repeat CBC with differential and a look at earlier results.

Reading neutrophils with your WBC and the rest of the differential

A neutrophil result is one line in a differential, and the lines around it change what it means.

Low ANC with a low total white count. Neutrophils make up the largest share of white cells, so a low neutrophil count often pulls the total down with it. The broader picture is covered in what a low white blood cell count means and the white blood cell count reference.

Low neutrophil % with high lymphocytes. This is common during and after a viral illness. Check the absolute neutrophil count first. If it is normal, the percentage moved because lymphocytes rose. The companion article on high lymphocytes covers that side.

Low ANC with anemia or low platelets. When more than one cell line is low, the bone marrow and nutritional causes such as B12 or folate deficiency move up the list. [1] This combination is a reason for prompt follow-up rather than routine retesting.

Other flagged white cell lines. If monocytes are low too, see low monocyte count causes. If immature granulocytes are flagged, see high immature granulocytes. For how the five main white cell types relate to each other, see the WBC differential explainer, and for the counts that call for urgent care, see dangerous WBC thresholds.

When to retest and how to read the trend

The first step for a low neutrophil count is a repeat CBC with differential, to rule out a lab error or a temporary dip, together with a look at your earlier results. [1] Time the repeat so it answers the question. After a viral illness, the count usually recovers within a couple of weeks, so retesting after you have fully recovered avoids catching the dip again. [1] If a new medicine is a possible cause, agree on the timing with your prescriber.

Read the series, not the latest value:

• Back in range after an illness: the temporary explanation fits, and nothing further is needed.
• Mildly low and stable for months or years with no infections: this points toward a constitutional pattern such as Duffy-null. A drop lasting three months or more is considered chronic. [1]
• Falling, or joined by other abnormal lines: this is the follow-up pattern described above, and the whole series is more useful to review than the latest result.

Trends are easiest to read when repeat tests come from the same lab, because reference intervals differ between labs. The Complete Blood Count (CBC) with Differential and Platelet Count Test reports both the Neutrophils % and Absolute Neutrophils lines, together with the white count, red cells, and platelets, which is the combination the patterns above depend on. Mito members pay our cost for lab tests. For a walk-through of every line on the report, see how to read CBC results.

If you are wondering whether you can raise your count, the answer depends on the cause. Diet and lifestyle questions are covered in how to improve your neutrophils naturally.

Frequently asked questions

How do you treat low neutrophils?

Treatment targets the cause, such as recovering from an infection, reviewing a medicine, or correcting a vitamin deficiency. Medicines that stimulate neutrophil production are reserved for people with more severe forms who have repeated serious infections. [3] A mild Duffy-null pattern needs no treatment. [2]

What cancers cause low neutrophils?

Blood and bone marrow cancers such as leukemia, lymphoma, and myeloma can lower neutrophils, and chemotherapy commonly does. [6] A mildly low count with otherwise normal blood counts is far more often explained by an infection, a medicine, or a constitutional pattern.

Is an ANC of 1.4 bad?

An ANC of 1.4 x10³/µL (1,400 cells per microliter) falls in the mild range. [3] On its own, with normal other counts and no symptoms, it is usually rechecked rather than treated. It can also be a normal value for someone with the Duffy-null phenotype. [5]

Can low neutrophils go back to normal?

Often, yes. A drop from a viral infection usually resolves within days to a couple of weeks, and a drug-related drop usually recovers within one to three weeks after the medicine is stopped. [1] A Duffy-null pattern does not change, because it is a lifelong normal variant. [2]

Do low neutrophils cause symptoms?

Often not. Many people with a low count have no symptoms at all. [3] The signs clinicians ask about are those of infection: fevers, mouth ulcers, gum problems, or skin infections. [1]

Bottom line

A low neutrophil flag on a routine CBC is usually mild. It is most often explained by a recent viral infection, a medicine, or a lifelong Duffy-null pattern that carries no added infection risk. [1] [2] Read the absolute count rather than the percentage, compare it with your lab’s range and your earlier results, and repeat the test once any illness has passed. Follow up promptly for a fever with a low count, a count below 1,000, a count that keeps falling, or other abnormal blood counts on the same report.

Sources

1. The Blood Project: Approach to Isolated Neutropenia
2. American Society of Hematology: Duffy-null Associated Neutrophil Count (DANC)
3. Kim MJ, Forlini C, Kremsreiter K. Neutropenia: Evaluation and Management in the Primary Care Setting. American Family Physician (2025)
4. American Family Physician: Evaluation of Patients with Leukocytosis (2015)
5. Merz LE, Osei MA, Story CM, et al. Development of Duffy Null–Specific Absolute Neutrophil Count Reference Ranges. JAMA (2023)
6. Cleveland Clinic: Neutropenia

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