By Michael Jung, PhD
Medically Reviewed By:
Dr. Ahmed Bokhari, MBBS, MPhil
Associate Professor, Postgraduate Medical Institute
Dr. Ahmed Bokhari is an Associate Professor of Medical Physiology with expertise in medical writing and patient education. He holds an MBBS degree from the University of Karachi and an MPhil in Physiology and has published research in peer-reviewed medical journals.
Seeing a low white blood cell (WBC) count on your complete blood count (CBC) test results is scary. It’s normal to worry that you’re sick or can’t fight infections well.
But if you haven’t been sick or had any infections, you should learn if your low white blood cell count is normal for you.
Some people are healthy, but their white blood cell count is naturally lower than the standard lab number. In these cases, having low white blood cell numbers doesn’t mean you can’t fight infections. It just means your “normal” white blood cell level is lower than the average lab range.
To understand how this can happen, it’s important to first know what white blood cells are.
What Are White Blood Cells?
White blood cells help you fight infections, viruses, and bacteria. They also help remove dead cells, parasites, toxins, and cancer cells.
Your bone marrow (the soft tissue in your bones) makes white blood cells. These cells then go into your blood and move to your organs to protect your body.
Your body makes different types of white blood cells, including:
- Neutrophils: These are the “first responders” that kill and break down bacteria and fungi
- Basophils: These cells tell other white blood cells to fight allergens and parasites by causing allergic reactions like sneezing or coughing.
- Eosinophils: These cells help fight parasites, allergic reactions, and cancer cells
- Lymphocytes: Different types of these cells fight viral infections and kill cancer cells
- Monocytes: These are your “cleanup crew” that get rid of damaged or dead cells
Neutrophils are the most common type of white blood cell and often the focus of low WBC counts.
What Could Cause a Low White Blood Cell Count in a Blood Test?
A CBC test counts the number of white blood cells in your blood draw and measures them per microliter of your blood. Many labs rate a white blood cell count between 4000 and 11,000 cells per microliter as “normal.” But this varies since different labs use different reference ranges.
If your test reports your white blood cell count is low, that means the number of white blood cells in your blood draw falls below the lab’s standard range. This is called leukopenia.
What is Leukopenia? (And What is Neutropenia?)
Leukopenia means you have a low number of white blood cells in your blood. This condition can be pathological (something caused by a disease or medical problem) or non-pathological (something not caused by a disease or medical problem).
Pathological causes for low white blood cell counts
- Autoimmune diseases that can make an immune system attack its own white blood cells
- A lack of a vitamin or mineral — like Vitamin B12, folate, or copper — that keeps your bone marrow from making new blood cells
- A swollen spleen that traps and destroys white blood cells
- Blood cancers like leukemia that keep bone marrow from making enough white blood cells
- Bacterial or viral infections that destroy white blood cells or use them up faster than they can be replaced
Non-pathological causes for low white blood cell counts
- Medications (like chemotherapy drugs) that lower white blood cell counts
- Leukopenia can occur during pregnancy
- Intense exercise that temporarily lowers white blood cell numbers
- Normal variations in certain populations that have lower WBC counts than other groups
Neutropenia is a type of leukopenia. It means you have a low number of neutrophils in your blood. Since neutrophils are the biggest part of your white blood cell count, neutropenia is the most common reason for a low white blood cell count.
Having fewer white blood cells can make it easier to get infections, causing symptoms like:
- High temperature
- Sore throat
- Mouth sores
- Toothache
- Skin rashes
- Tiredness
- Flu-like symptoms
If you get any of these symptoms, call your doctor or get emergency medical care right away.
But if you don’t have these symptoms, your white blood cell count may have a harmless reason.
Can Having a Low WBC Count in a CBC Test Be Normal?
Lab reference ranges for “normal” cell counts are based on 95% of the population. This means 5% of healthy people fall outside these numbers.
If you’re healthy but have a low white blood cell count, this could mean you have:
DANC (Aka. “Benign Ethnic Neutropenia”)
DANC — or Duffy-null Associated Neutrophil Count — is a normal, healthy genetic condition where a person has fewer neutrophils in their bloodstream.
People with DANC may have lower circulating neutrophil levels even though they maintain normal immune function. The total number of neutrophils is often normal, but since many of their neutrophils aren’t moving through their blood, they don’t show up in a blood test.
DANC comes from a natural adaptation to help people fight disease in places affected by malaria. DANC does not turn into leukemia or a bone marrow disorder and is a lifelong, stable pattern.
DANC appears among many people with African ancestry and is also seen in some Middle Eastern and Mediterranean populations. This makes DANC a common healthy state.
People with DANC have normal immune systems and are not at increased risk of infections. Most do not need treatment or restrictions. However, having a qualified clinician confirm the diagnosis is important.
(DANC was once called Benign Ethnic Neutropenia (BEN) but was renamed to focus on science, not race.)
CIN
CIN (Chronic Idiopathic Neutropenia) is when a person’s blood has a low number of neutrophil white blood cells. “Chronic” means CIN lasts at least 3 months and “Idiopathic” means the cause is unknown.
CIN’s exact cause is often unknown and may involve different factors. However, it’s not a form of cancer and is often considered harmless.
Most people with CIN don’t have problems with infections. Even if their neutrophil count is low, they still make enough white blood cells to stay healthy.
But if a person’s neutrophil count drops to a very low level, they could be at greater risk of infection. If this happens, they can get medication. This may be a G-CSF (Granulocyte Colony-Stimulating Factor), a man-made hormone that gets the bone marrow to make more neutrophils.
Pseudoneutropenia
Sometimes, a blood test shows a false low count of neutrophil white blood cells. This is called Pseudoneutropenia (“false low neutrophil count”).
This can happen if neutrophils temporarily shift out of circulation due to stress, exercise, or certain medications. Neutrophils can also get damaged during testing, affecting measurement.
If your low white blood cell count is because the blood test is wrong, you’re at no increased infection risk. Your doctor may need to repeat the test to confirm.
What Should You Do If You See a Low WBC in Your CBC Test?
If you get a low white blood cell count on your blood test, your doctor needs to rule out different causes. You can help by:
Getting Tested by Your Doctor
Doctors need to check for any one of several possible causes for your low white blood cell count. Every cause has its own test.
Many tests are non-invasive and don’t need surgery. Getting these first (and confirming the reason for your low WBC count) can help prevent the need for invasive procedures that go into your body (like bone marrow biopsies).
Your doctor may order:
- Multiple CBC tests to see if your low white blood cell count is temporary or long-term
- WBC differentials that look at your different white blood cells to learn which one(s) are low
- Peripheral blood smears that check the shapes of your blood cells to see if they look healthy
- A physical exam to see if you show signs of illness or infection
- A review of your medication history to see if your medications could lower blood cell counts
- Nutritional tests to check for vitamin or mineral shortages
If you’re healthy but your ethnic background matches people who commonly have DANC, then you may receive Duffy antigen phenotyping. This test checks to see if your red blood cells lack a certain protein that shows you have DANC. Since DANC is rare compared to other possible low WBC causes, this test usually comes last.
Asking Your Doctor Questions
Ask questions about your test results. Start with:
- Is my white blood cell count low enough to increase my infection risk?
- How does this result compare to my other blood tests?
- Are my other blood levels (red blood cells, platelets) normal?
- What happens if I take medications that lower neutrophils?
Anticipating Your Doctor’s Questions
Your doctor may also ask you questions about your symptoms and medical history. Be prepared to answer healthcare provider queries like:
- Are there any other symptoms, like bleeding, joint pain, or swelling?
- Do these symptoms happen on and off (episodically) or constantly?
- Did you have a complete blood count (CBC) test done before this one? Was there any dramatic shift in white blood cell counts or other results?
Following Healthy Practices
Infection precautions are usually only needed for people with very low neutrophil counts or patients getting treatments that weaken their immune system. Follow your doctor’s guidance — it’s possible you may need to change medications or eat foods with nutrients that help make more white blood cells.
Updating Your Medical Records
If you have a harmless condition like DANC, make sure it’s recorded in your permanent medical record. This prevents unnecessary repeat testing, avoids surgical delays, and makes sure you aren’t unfairly excluded from clinical drug trials.
Learning You Have a Low WBC Count
A low white blood cell result is frightening, but if you feel well, it could be your normal healthy baseline. By working with your doctor to rule out illness, you can gain peace of mind and learn how to manage your health — whether that means a simple diet change or a note in your medical file.
References
- Kumar, V., Abbas, A. K., Aster, J. C., & Deyrup, A. T. (Eds.). (2022). Robbins & Kumar Basic Pathology, E-Book. Elsevier Health Sciences.
- Mescher, A. L. (2024). Junqueira’s Basic Histology: Text and Atlas.
- https://my.clevelandclinic.org/health/body/21871-white-blood-cells
- https://medlineplus.gov/ency/article/003643.htm
- https://karger.com/fdt/article-abstract/20/6/540/135837/Systemic-Lupus-Erythematosus-Associated-Acute?redirectedFrom=fulltext
- https://www.nhs.uk/conditions/low-white-blood-cell-count/
- https://www.jabfm.org/content/38/1/174.full
- https://ashpublications.org/blood/article/146/Supplement%201/6567/548906/Characterizing-benign-ethnic-neutropenia-using-a
- https://pmc.ncbi.nlm.nih.gov/articles/PMC5380401/
- https://pubmed.ncbi.nlm.nih.gov/33219405/
Disclaimer: I am a content writer, not a doctor or hematologist. The information in this article is for educational and informational purposes only and should not be considered medical advice, diagnosis, or treatment. Always seek the advice of your physician or qualified health provider with questions regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you read here.
Medical Reviewer’s Assessment:
“Very accurate and fully supported by literature.”
— Dr. Ahmed Bokhari, MBBS, MPhil, Associate Professor of Medical Physiology