White Blood Cell Differential Count (Differential, Diff)

The white blood cell differential count determines the number of each type of white blood cell, present in the blood. It can be expressed as a percentage (relative numbers of each type of WBC in relationship to the total WBC) or as an absolute value (percentage x total WBC). Of these, the absolute value is much more important than the relative value. There are five basic white blood cell types: Neutrophils Eosinophils Basophils Lymphocytes Monocytes Each WBC cell type has its' own unique features. Neutrophils (Segmented Neutrophils, Segs, Polymorphonucleocytes, Polymorphonuclear Neutrophils, Polys, PMNs) These are the most common of the WBCs and serve as the primary defense against infection. The typical response to infection or serious injury is an increased production of neutrophils. Bands/Stabs Early in the response to infection, immature forms of neutrophils will be seen. These are call Stab or Band cells. The presence of these immature cells is called a "shift to the left" and can be the earliest sign of a WBC response, even before the WBC becomes elevated. Eosinophils (Eos) These cells play a role in allergic disorders and in combating parasitic infections. Elevations in eosinophil counts are associated with: Allergic reactions Parasite infections Chronic skin infections Some cancers Decreases in eosinophil counts are associated with: Stress Steroid exposure Anything that may suppress WBC production generally Basophils (Baso's) These cells can digest bacteria and other foreign bodies (phagocytosis) and also have some role in allergic reactions. Elevations in basophil counts are associated with: Some cancers Some allergic reactions Some infections Radiation exposure Diminished basophil counts are associated with: Stress reactions Some allergic reactions Hyperthyroidism Prolonged steroid exposure Monocytes (Mono's) These cells respond to inflammation, infection and foreign bodies by ingesting and digesting the foreign material. Increased monocyte counts are associated with: Recovery from an acute infection Viral illness Parasitic infections Collagen disease Some cancers Decreased monocyte counts are associated with: HIV infection Rheumatoid arthritis Steroid exposure Some cancers Lymphocytes (Lymphs) These cells play both an immediate and delayed role in response to infection or inflammation. Increased numbers of lymphocytes are seen in: Most viral infections Some bacterial infections Some cancers Graves' disease Decreased numbers of lymphocytes are seen in: Steroid exposure Some cancers Immunodeficiency Renal failure Lupus

Normal Values* Neutrophils #/cubic mm % Men 3,000-7,000 50-60 Women 1,800-7,700 50-60 Pregnancy 3,800-10,000 50-60 Infant 1,000-8500   8 year old 1,500-8000   Bands/Stabs % Men 0-3% Women 0-3% Pregnancy 0-3% Eosinophils #/cubic mm % Men 50-250 1-4 Women 0-450 0-4 Pregnancy 0-450 0-4  Basophils #/cubic mm % Men 25-100 0.5-1.0 Women 25-100 0.5-1.0 Pregnancy 25-100 0.5-1.0  Monocytes #/cubic mm % Men 100-600 2-6 Women 0-800 0-8 Pregnancy 0-800 0-8  Lymphocytes #/cubic mm % Men 1,000-4,000 20-40 Women 1,000-4,800 20-50 Pregnancy 1,300-5,200 20-50 Older Children 1,000-7,000   Infants 1,000-9,000   *These are general values taken from a variety of sources. The actual normal values may vary from lab to lab and from one type of testing protocol to another. Development of Blood Cells