Monday, April 16, 2007

Segmented Neutrophils

in peripheral smear
Segmented Neutrophils
 (Polymorphonuclear Neutrophils, PMNs, Segs, Polys)
Neutrophils, the most numerous and important type of leukocytes in the body's reaction to inflammation, constitute a primary defense against microbial invasion through the process of phagocytosis. These cells can also cause some body tissue damage by their release of enzymes and endogenous pyogenes. In their immature stage of development, neutrophils are referred to as "stab" or "band" cells. The term band stems from the appearance of the nucleus, which has not yet assumed the lobed shape of the mature cell.
This test determines the presence of neutrophilia or neutropenia. Neutrophilia is an increase in the absolute number of neutrophils in response to invading organisms and tumor cells. Neutropenia occurs when too few neutrophils are produced in the marrow, too many are stored in the blood vessel margin, or too many have been called to action and used up.
Reference Values
Normal Absolute count: 3000–7000/mm 3 or 3–7 × 10 9/L

All references are using this SI unit for reporting.

Black adults: 1.2–6.6 × 10 9/L Differential: 50% of total WBC 0%–3% of total PMNs are stab or band cells

1.Obtain a 5-mL blood sample in EDTA coagulant and place it in biohazard bag.

2.Count as part of the differential.
Clinical Implications

1.Neutrophilia (increased absolute number and relative percentage of neutrophils) >8.0 × 10 9/L or 8000/mm 3; for African Americans: >7.0 × 10 9/L or 7000/mm 3

        a.Acute, localized, and general bacterial infections. Also, fungal and spirochetal and some parasitic and rickettsial infections.

        b.Inflammation (eg, vasculitis, rheumatoid arthritis, pancreatitis, gout), and tissue necrosis (myocardial infarction, burns, tumors).

        c.Metabolic intoxications (eg, diabetes mellitus, uremia, hepatic necrosis)

        d.Chemicals and drugs causing tissue destruction (eg, lead, mercury, digitalis, venoms)

        e. Acute hemorrhage, hemolytic anemia, hemolytic transfusion reaction

        f.Myeloproliferative disease (eg, myeloid leukemia, polycythemia vera, myelofibrosis)

        g.Malignant neoplasms—carcinoma

        h.Some viral infections (noted in early stages) and some parasitic infections

2.Ratio of segmented neutrophils to band neutrophils: normally 1%–3% of PMNs are band forms (immature neutrophils).

        a.Degenerative shift to left: in some overwhelming infections, there is an increase in band (immature) forms with no leukocytosis (poor prognosis).

        b.Regenerative shift to left: there is an increase in band (immature) forms with leukocytosis (good prognosis) in bacterial infections.

        c.Shift to the right: decreased band (immature) cells with increased segmented neutrophils can occur in liver disease, megaloblastic anemia, hemolysis, drugs, cancer, and allergies.

        d.Hypersegmentation of neutrophils with no band (immature) cells is found in megaloblastic anemias (eg, pernicious anemia) and chronic morphine addiction.

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