Differential; Diff; White blood cell differential count 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. 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 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 of all white cells:
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. Abnormal or immature white blood cells may indicate leukemia or bone marrow invasion by cancer or infection. 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. 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. | |
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Review Date: 2/2/2023 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. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | |
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