Differential; Diff; White blood cell differential count 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. Basophils are a specific type of white blood cell. These cells are readily stained with basic dyes (this is where the name comes from). Note the dark grains inside the cellular fluid (cytoplasm) of this basophil. Basophils make up only a small portion of the number of white blood cells but are important parts of the body's immune response. They release histamine and other chemicals that act on the
blood vessels when the immune response is triggered. Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide. Blood
distributes nearly everything that is carried from one area in the body to another place within the body. For example, blood transports hormones from endocrine organs to their target organs and tissues. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection. The White Blood Cell (WBC) Count measures two components; the total number of WBC's (leukocytes) and the differential count. The differential count measures the percentages of each type of leukocyte present. WBC's are composed of
granulocytes (neutrophils, eosinophils, and basophils) and non-granulocytes (lymphocytes and monocytes). White blood cells are a major component of the body's immune system. Indications for a WBC count include infectious and inflammatory diseases; leukemia and lymphoma; and bone marrow disorders. A
blood sample is needed. A 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:
A special machine or a health care provider 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 TestNo special preparation is necessary. How the Test will FeelWhen 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 PerformedThis 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. Normal ResultsThe different types of white blood cells are given as a percentage:
What Abnormal Results MeanAny 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. It 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:
A decreased percentage of neutrophils may be due to:
An increased percentage of lymphocytes may be due to:
A decreased percentage of lymphocytes may be due to:
An increased percentage of monocytes may be due to:
An increased percentage of eosinophils may be due to:
An increased percentage of basophils may be due to:
A decreased percentage of basophils may be due to:
RisksThere 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:
ReferencesBain BJ. The peripheral blood smear. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 148. Chernecky CC, Berger BJ. Differential leukocyte count (diff) - peripheral blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:440-446. 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. Version InfoLast reviewed on: 1/19/2021 Reviewed by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. What is considered a high monocyte count?An absolute monocyte count above 10 percent , or 800 per mm3, is considered high. It's called monocytosis and might mean your body is responding to something.
What is the normal percentage of monocytes in blood?Normal Results
The different types of white blood cells are given as a percentage: Neutrophils: 40% to 60% Lymphocytes: 20% to 40% Monocytes: 2% to 8%
Should I be worried if my monocytes are high?A high monocyte count is a potential sign of many different medical conditions. It's often linked to infectious diseases like mononucleosis or an autoimmune disease like lupus. Some medications can cause monocytosis. It's also linked to conditions such as blood disorders and certain cancers.
What level of monocytes indicate leukemia?A common sign of CMML is a high number of monocytes, greater than 1,000 per microliter. Other signs include low numbers of other white blood cells, red blood cells, and blood platelets.
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