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You are watching: The terms crenation, poikilocytosis, and anisocytosis all refer to:

Walker HK, room WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990.


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Definition

Examination the the peripheral blood smear should be considered, along with review of the results of peripheral blood counts and red blood cabinet indices, an important component the the initial evaluation of every patients v hematologic disorders. The check of blood films stained v Wright"s stain frequently provides important ideas in the diagnosis of anemias and also various obstacle of leukocytes and platelets.

Normal human being red blood cells room biconcave disks (diskocytes) through a typical diameter of about 7.5 μm. Erythrocytes space slightly smaller than little lymphocytes. The hemoglobin of red cells is located peripherally, leaving an area of central pallor equal to about 30 to 45% of the diameter of the cells. Cells of typical size and hemoglobin content (color) are termed normocytic and also normochromic. Bigger than common erythrocytes space macrocytes (diameter greater than 9 μm); small red cells space microcytes (diameter much less than 6 μm); and those with central pallor better than 50% of the diameter space hypochromic. Abnormal variability in size is termed anisocytosis; unexplained variation in shape is dubbed poikilocytosis; and significant differences among erythrocytes in the lot of central pallor is referred to as anisochromia. Polychromatophilia means the erythrocytes have actually a blue-gray hue to the shade of their cytoplasm.

From a diagnostic standpoint, poikilocytosis has no specificity, yet the recognition of certain forms that poikilocytes (irregularly shaped cells) regularly points to specific disorders. Spherocytes are round, densely staining red cells that lack main pallor and also have a smaller sized than regular diameter. In stomatocytes, the area of main pallor is elliptical fairly than round, offering the cabinet the illustration of the opened of a mouth (stoma). Target cell (codocytes) have actually a centrally located disk that hemoglobin surrounding by one area the pallor with an outer rim that hemoglobin nearby to the cabinet membrane offering the cell the appearance of a target. Leptocytes (or wafer cells) are thin, flat cells with the hemoglobin at the periphery of the cell. Sickle cell (drepanocytes) are elongated, periodically crescent-shaped, erythrocytes v pointed ends. Elliptocytes (ovalocytes) range from slightly oval come elongated cigar-shaped forms. Teardrop erythrocytes (dacryocytes) space red cells v one end round and also the other end more pointed. Acanthocytes have several (usually 3 to 7) irregularly spaced blunted projections native the margin that the cells. Echinocytes are likewise cells v cytoplasmic projections, but in comparison to acanthocytes, the projections are frequently evenly spaced on the cell surface, much more numerous (often 10 to 15), and also frequently have sharper points. Schizocytes (schistocytes) are fragmentized erythrocytes appearing in a range of morphologic forms such as little triangular erythrocytes, helmet cells, and normal-size erythrocytes v 2 come 3 pointed surface projections (keratocytes, or "horn cells"). Round erythrocytes with a single, elliptical or round surface defect space termed bite cells. Rouleaux formation is a expression denoting the stacking the erythrocytes, usually in a curving pattern.

Morphologic to know of inclusion bodies within erythrocytes can be helpful clinically. Howell–Jolly bodies are purple spheres, usually around 0.5 μm in diameter, presenting singly, or seldom multiply, in the cytoplasm. Basophilic stippling that erythrocytes advert to numerous very tiny coarse or good blue granules within the cytoplasm. As soon as the stippled particles are due to iron granules (demonstrable through the Prussian blue stain), they room termed Pappenheimer bodies. Malaria parasites may show up as cytoplasmic inclusion bodies in ~ erythrocytes. Platelets overlying erythrocytes might be mistaken for erythrocyte inclusions.

There are a number of important morphologic abnormalities of maturation granulocytes. Cytoplasmic vacuoles might be recognized. Toxicity granulation refers to small, dark blue-staining granules. Döhle bodies space light blue cytoplasmic inclusions, 1 to 2 μm in diameter. The Pelger–Huët anomaly, a disorder defined by impaired atom segmentation of maturation neutrophilic granulocytes, shows up morphologically as cells through bilobed nuclei (dumbbell or eyeglass shapes) or v round or oval nuclei (Stodtmeister cells). Hypersegmented neutrophils space cells in which over there are 6 or more nuclear lobes.

Reactive lymphocytes space usually bigger than small lymphocytes, may have actually cytoplasmic vacuolization, sometimes have deep blue staining the the perimeter of the cytoplasm, and also contain nuclei that may be kidney p or monocytoid in shape.

Most platelets in the peripheral blood have actually diameters in between 1 and also 3 μm. Platelets better than 3 μm in diameter room "large" (megathrombocytes). In a normal human being usually less than 5% the the platelets appear large.

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Figure 155.1 shows examples of shape normal and also abnormal erythrocytes.