Blood differential test
The blood differential test measures the percentage of each type of white blood cell (WBC) that you have in your blood. It also reveals if there are any abnormal or immature cells.
How the Test is Performed
A blood sample is needed.
Blood sample
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
Read Article Now Book Mark ArticleA laboratory specialist takes a drop of blood from your sample and smears it onto a glass slide. The smear is stained with a special dye, which helps tell the difference between various types of white blood cells.
Five types of white blood cells, also called leukocytes, normally appear in the blood:
- Neutrophils
- Lymphocytes (B cells and T cells)
- Monocytes
- Eosinophils
- Basophils
A special machine counts the number of each type of cell. The test shows if the number of cells are in proper proportion with one another, and if there is more or less of one cell type.
How to Prepare for the Test
No special preparation is necessary.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.
Why the Test is Performed
This test is done to diagnose an infection, anemia, or leukemia. It may also be used to monitor one of these conditions or to see if treatment is working.
Anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...
Read Article Now Book Mark ArticleLeukemia
Leukemia is a type of blood cancer that begins in the bone marrow. Bone marrow is the soft tissue in the center of the bones, where blood cells are ...
Read Article Now Book Mark ArticleNormal Results
The different types of white blood cells are given as a percentage of all white cells:
- Neutrophils: 40% to 60%
- Lymphocytes: 20% to 40%
- Monocytes: 2% to 8%
- Eosinophils: 1% to 4%
- Basophils: 0.5% to 1%
- Band (young neutrophil): 0% to 3%
What Abnormal Results Mean
Any infection or acute stress increases your number of white blood cells. High white blood cell counts may be due to inflammation, an immune response, or blood diseases such as leukemia. Abnormal or immature white blood cells may indicate leukemia or bone marrow invasion by cancer or infection.
Acute
Acute means sudden. Acute symptoms appear, change, or worsen rapidly. It is the opposite of chronic.
Read Article Now Book Mark ArticleImmune response,
The immune response is how your body recognizes and defends itself against bacteria, viruses, and substances that appear foreign and harmful....
Read Article Now Book Mark ArticleIt is important to realize that an abnormal increase in one type of white blood cell can cause a decrease in the percentage of other types of white blood cells.
An increased percentage of neutrophils may be due to:
- Acute infection
- Inflammation
- Acute stress
- Eclampsia (seizures or coma in a pregnant woman)
Eclampsia
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Gout
Gout is a type of arthritis. It occurs when uric acid builds up in the blood and causes inflammation in the joints. Acute gout is a painful conditio...
Read Article Now Book Mark Article - Acute or chronic forms of leukemia
- Myeloproliferative diseases
- Rheumatoid arthritis
Rheumatoid arthritis
Rheumatoid arthritis (RA) is a disease that leads to inflammation of the joints and surrounding tissues. It is a long-term disease. It can also aff...
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Rheumatic fever
Rheumatic fever is a disease that may develop after an infection with group A streptococcus bacteria (such as strep throat or scarlet fever). It can...
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Thyroiditis
Chronic thyroiditis is caused by a reaction of the immune system against the thyroid gland. It often results in reduced thyroid function (hypothyroi...
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- Cigarette smoking
A decreased percentage of neutrophils may be due to:
- Aplastic anemia
Aplastic anemia
Aplastic anemia is a condition in which the bone marrow does not make enough blood cells. Bone marrow is the soft, tissue in the center of bones tha...
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Chemotherapy
The term chemotherapy is used to describe cancer-killing drugs. Chemotherapy may be used to:Cure the cancerShrink the cancerPrevent the cancer from ...
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Influenza
The flu (influenza) is a viral respiratory illness that causes fever, chills, runny nose, body aches, and cough. It spreads easily from person to pe...
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Radiation therapy
Radiation therapy uses high-powered radiation (such as x-rays or gamma rays), particles, or radioactive seeds to kill cancer cells.
Read Article Now Book Mark Article - Viral infection
- Widespread severe bacterial infection (sepsis)
An increased percentage of lymphocytes may be due to:
- Chronic bacterial infection
Chronic
Chronic refers to something that continues over an extended period of time. A chronic condition is usually long-lasting and does not easily or quick...
Read Article Now Book Mark Article - Infectious hepatitis (liver swelling and inflammation from bacteria or viruses)
- Infectious mononucleosis, or mono (viral infection that causes fever, sore throat, and swollen lymph glands)
Infectious mononucleosis
Mononucleosis, or mono, is a viral infection that causes fever, sore throat, and swollen lymph glands, most often in the neck.
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Tuberculosis
Pulmonary tuberculosis (TB) is a contagious bacterial infection that involves the lungs. It may spread to other organs.
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Lymphocytic leukemia
Acute lymphoblastic leukemia (ALL) is a fast-growing cancer of a type of white blood cells called lymphocytes. ALL occurs when the bone marrow produ...
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Multiple myeloma
Multiple myeloma is a blood cancer that starts in the plasma cells in the bone marrow. Bone marrow is the soft, spongy tissue found inside most bone...
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Mumps
Mumps is a contagious disease that leads to painful swelling of the salivary glands. The salivary glands produce saliva, a liquid that moistens food...
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Measles is a very contagious (easily spread) illness caused by a virus.
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A decreased percentage of lymphocytes may be due to:
- Chemotherapy
Chemotherapy
The term chemotherapy is used to describe cancer-killing drugs. Chemotherapy may be used to:Cure the cancerShrink the cancerPrevent the cancer from ...
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HIV/AIDS
Human immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). When a person becomes infected with HIV, the ...
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- Radiation therapy or exposure
Radiation therapy
Radiation therapy uses high-powered radiation (such as x-rays or gamma rays), particles, or radioactive seeds to kill cancer cells.
Read Article Now Book Mark Article - Sepsis (severe, inflammatory response to bacteria or other germs)
Sepsis
Sepsis is an illness in which the body has a severe, inflammatory response to bacteria or other germs.
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An increased percentage of monocytes may be due to:
- Chronic inflammatory disease
- Leukemia
- Parasitic infection
- Tuberculosis, or TB (bacterial infection that involves the lungs)
Tuberculosis
Pulmonary tuberculosis (TB) is a contagious bacterial infection that involves the lungs. It may spread to other organs.
Read Article Now Book Mark Article - Viral infection (for example, infectious mononucleosis, mumps, or measles)
Mononucleosis
Mononucleosis, or mono, is a viral infection that causes fever, sore throat, and swollen lymph glands, most often in the neck.
Read Article Now Book Mark ArticleMumps
Mumps is a contagious disease that leads to painful swelling of the salivary glands. The salivary glands produce saliva, a liquid that moistens food...
Read Article Now Book Mark ArticleMeasles
Measles is a very contagious (easily spread) illness caused by a virus.
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An increased percentage of eosinophils may be due to:
- Addison disease (adrenal glands do not produce enough hormones)
Addison disease
Addison disease is a disorder that causes the adrenal glands to not produce enough hormones.
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Allergic reaction
Allergic reactions are sensitivities to substances called allergens that come into contact with the skin, nose, eyes, respiratory tract, and gastroin...
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Cancer
Cancer is the uncontrolled growth of abnormal cells in the body. Cancerous cells are also called malignant cells.
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Chronic myelogenous leukemia
Chronic myelogenous leukemia (CML) is cancer that starts inside the bone marrow. This is the soft tissue in the center of bones that helps form all ...
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Collagen vascular disease
In a class of diseases known as autoimmune disorders, the body's immune system attacks its own tissues. Some of these diseases are similar to each o...
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- Parasitic infection
An increased percentage of basophils may be due to:
- After splenectomy
Splenectomy
Post-splenectomy complications can occur after surgery to remove the spleen. Complications may include: Blood clotsDestruction of red blood cellsInc...
Read Article Now Book Mark Article - Allergic reaction
Allergic reaction
Allergic reactions are sensitivities to substances called allergens that come into contact with the skin, nose, eyes, respiratory tract, and gastroin...
Read Article Now Book Mark Article - Chronic myelogenous leukemia (a type of bone marrow cancer)
Chronic myelogenous leukemia
Chronic myelogenous leukemia (CML) is cancer that starts inside the bone marrow. This is the soft tissue in the center of bones that helps form all ...
Read Article Now Book Mark Article - Collagen vascular disease
Collagen vascular disease
In a class of diseases known as autoimmune disorders, the body's immune system attacks its own tissues. Some of these diseases are similar to each o...
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- Chickenpox
Chickenpox
Chickenpox is a viral infection in which a person develops very itchy blisters all over the body. It was more common in the past. The illness is ra...
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A decreased percentage of basophils may be due to:
- Acute infection
- Cancer
- Severe injury
Risks
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Multiple punctures to locate veins
- Hematoma (blood accumulating under the skin)
Hematoma
A bruise is an area of skin discoloration. A bruise occurs when small blood vessels break and leak their contents into the soft tissue beneath the s...
Read Article Now Book Mark Article - Infection (a slight risk any time the skin is broken)
Reviewed By
Mark Levin, MD, Hematologist and Oncologist, Monsey, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Bain BJ. The peripheral blood smear. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 148.
Nasr MR, Hutchison RE. Leukocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 34.