DefinitionThe 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. Show Alternative NamesDifferential; Diff; White blood cell differential count How the Test is PerformedA 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:
ReferencesChernecky 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. Hutchison RE, Schexneider KI. Leukocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 33. What is the normal percentage of lymphocytes in blood?Normal Results
Neutrophils: 40% to 60% Lymphocytes: 20% to 40%
What is the alarming level of lymphocytes?A count significantly higher than 3,000 lymphocytes in a microliter of blood is generally considered to be lymphocytosis in adults. In children, the threshold for lymphocytosis varies with age. It can be as high as 9,000 lymphocytes per microliter.
What is a low range for lymphocytes?If your lymphocyte count is less than 1,000 lymphocytes per microliter of blood, this is generally considered to be lymphocytopenia in adults. In children, a low lymphocyte count is when it's less than 3,000 lymphocytes per microliter of blood.
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