Blood

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This slide shows four of the five different types of white blood cells found in the peripheral blood. The types of white blood cells are considered in two categories:
Granulocytes - This group includes the neutrophils, eosinophils, and basophils. These cells are distinguished by the presence of azurophilic granules, thought to be lysosomes, and specific granules. Specific granules stain with neutral or acid dye components and contain various enzymes. The specific granules allow the three cell types to be distinguished.
Agranulocytes - These are the monocytes and lymphocytes. They contain azurophilic, but not specific, granules.

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Lymphocytes and Monocyte, Giemsa, 330x

This slide shows the different sizes of lymphocytes. Lymphocytes are identified by the presence of a spherical nucleus that may have an indentation. The nucleus is very condensed and stains darkly. The cytoplasm is scanty, appearing as a rim around the nucleus. The cytoplasm generally stains a pale "robin's egg" blue as it is slightly basophilic.
A monocyte is seen in the field as well. They generally have a lighter staining nucleus as the chromatin is much less condensed. The nucleus is generally eccentrically placed in the cell. It is irregularly shaped, usually oval or kidney bean shaped. The monocyte has much more cytoplasm than the lymphocyte.
 

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Cell number one is a monocyte. Again, note the kidney shaped nucleus, eccentrically located. It appears lacy as the chromatin is not very condensed. It is a large cell with a lot of cytoplasm.
Monocytes are the precursors in the blood of the cells of the mononuclear phagocyte system. Upon leaving the blood and entering the connective tissue, they differentiate into macrophages.

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Cell number one is one of the members of the granulocyte group, a neutrophil.
The neutrophil has a segmented nucleus, with anywhere from 3-5 lobes connected by thin threads of chromatin. The chromatin is densely arranged around the edges and loosely arranged in the center.
The specific granules are small, and usually spherical. They stain neutrally, picking up both the acid and basic components. This results in the granules having a purplish color with Wright's stain. However, they usually are not well seen in our slides.

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What is cell number two?

ANSWER:

A monocyte -- look at the shape, position, and the lacy staining of the nucleus as well as the amount of cytoplasm.

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This slide shows a mature neutrophil and an almost mature neutrophil known as a band form. The nucleus is not yet lobulated. The nucleus resembles a monocyte nucleus, but it is smaller and the chromatin is more condensed.
The other cell is a second member of the granulocytes, the eosinophil. Its nucleus generally has two lobes, sometimes three. It has large specific granules that stain with acid dyes like... eosin.

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Another eosinophil with a bilobed nucleus and larger, acid - staining granules. The larger specific granules generally mask the azurophilic ones.

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This is the final granulocyte, the basophil. They are relatively rare, making up less than 1% of the WBC's found on a smear. They have large granules that stain with basic dyes. The nucleus does contain irregular lobes, but these lobes aren't generally seen as the specific granules usually obscure the nucleus

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A basophil is seen again, identifiable by the granules completely obscuring the nucleus.
A neutrophil with multilobed nucleus and small granules is seen next to it.
The staining appearance is not the same as previously seen. One hint, to get a feel for the staining, is to look at the color of the RBC's. Here they are yellow-blue rather than pink-red as they were in the previous slide. In line with that, the other cells don't appear as red or purple as they might in other examples.

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1 is a lymphocyte - intensely staining nucleus with a thin rim of cytoplasm
2,5,6 are monocytes - note the variety in the nucleus' shape
3,4 are neutrophils - note the multilobulated nucleus, lavender cytoplasm

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Cell 1 - Monocyte - lacy staining, irregularly shaped nucleus
Cells 2 and 3 - Neutrophils - multilobed nucleus, fine granules.
Cell 4 - Lymphocyte - scant cytoplasm, dense nucleus

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ssa

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Megakaryocyte clearly seen surrounded by other blood cell precursors which are to be discussed shortly.
The structure of the nucleus reflects its polyploidy (as many as 32 replications of the chromosomes may occur without cell division!!)

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but what is cell 1?

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A mature eosinophil -- big granules, three lobes. Bone marrow has mostly immature cells with some mature ones occasionally seen on their way out.

The cells labelled number three are platelets. They are disc-like cell fragments from the megakaryocyte. They lack a nucleus and contain various granules in their cytoplasm. They play a role in clotting of blood.
 
Cell 2 is a developing neutrophil (probably),

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The earliest precursor is the blast cell, a proerythroblast in the RBC series and a myeloblast in the granulocyte series. These two blasts are not easily distinguished. They are large cells with loose chromatin and clearly visible nucleoli (not too clear here). Their cytoplasm stains a light blue.

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Why are there fewer azurophilic granules in the myelocyte stage?

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Azurophilic granules only form during the promyelocyte stage and therefore, with each successive division their numbers per cell decrease

We begin with the neutrophilic developmental series.
The next stage after the blast cell is the promyelocyte. The cytoplasm is basophilic with prominent azurophilic granules. The nucleus is rounded and more condensed than in the blast. the nucleolus is not as visible. The promyelocyte can differentiate into any of the three granulocytes.
The next stage is the myelocyte. A myelocyte is neutrophilic, eosinophilic, or basophilic. This neutrophilic myelocyte is an early one. The nucleus is slightly indented and the chromatin is even more condensed. The cytoplasm has fewer azurophilic granules and specific granules are starting to appear.

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#1 is a promyelocyte. Granules can be seen although the cytoplasm is more basophilic than before.
#2 and 3 are neutrophilic myelocytes. The specific granules are the small purplish ones of a neutrophil, there are few azurophilic granules, the nucleus has become more condensed, and there is an indentation in the nucleus. #3 is a later one, as it is smaller with a larger indentation in the nucleus.
#4 and 5 represent the next stage of neutrophil development, the neutrophilic metamyelocyte. The cell has decreased in size, has a more prominent indentation in the nucleus and the chromatin is much more condensed.
#6 is a mature neutrophil
#7 and 8 are actually in the erythrocyte series to be discussed soon. For the curious, they are normoblasts (orthochromatic erythrocytes).

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Identify 2 and 3.

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2 is a late promyelocyte/early neutrophilic myelocyte. There are still alot of azurophilic granules, but the nucleus is starting to flatten out.
3 is a neutrophilic metamyelocyte. It is small with a very indented nucleus and mostly specific granules.

Cell 1 is a promyelocyte (note the granules, nucleus is not indented). This promyelocyte is currently undergoing mitosis.
Cell 4 is an early normoblast of the red cell series. What are 2 and 3? Look at the question (actually I guess the answer will be more helpful).
 

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What are cells 1, 2, 3, 5, and 6?

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#1 and 2 are promyelocytes - loose chromatin, eccentric nucleus, slightly basophilic cytoplasm, azurophilic granules.
#3 is a neutrophilic metamyelocyte (indisputably) - few azurophilic granules, condensed and clearly indented nucleus, smaller size.
#5 and 6 are mature neutrophils - multilobed nucleus, small, purplish specific granules

Cell 4 is the last stage of neutrophil development, the band cell. This cell is unique to the neutrophilic development series. The nucleus indents so far as to appear as a thin curved rod. These appear in the blood if there is a strong stimulation of hematopoiesis, for example, in cases of bacterial infection. This is referred to as a shift to the left, a term you will use again in microbiology (be psyched!)
For those of you who are kicking the screen because you were 100% sure that was a neutrophilic metamyelocyte, relax, you weren't really wrong. This cell technically could be considered a very late neutrophilic metamyelocyte/early band cell. Borderline cells happen often when distinguishing these stages. As a result, answers are somewhat more subjective and this is taken into account on a practical (i.e.late metamyelocyte could be argued for. Mature neutrophil could not).

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Identify all the white blood cells (they're the ones with the numbers).

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#1-Two promyelocytes - azurophilic granules, eccentric nucleus, not too condensed chromatin.
#2-Three mature neutrophils - multilobed nuclei, small lilac specific granules
#3-Four neutrophilic metamyelocytes - indented nucleus, condensed chromatin, few azurophilic granules.
#4-Two neutrophilic myelocytes - flattenened, not indented nucleus, condensed chromatin, few azurophilic granules

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Welcome to the eosinophilic series. It starts with the myeloblast and the promyelocyte just as the neutrophilic series did. At the myelocyte stage, its unique specific granules appear and it is recognizable as a member of the eosinophilic lineage. Both cell 1 and 2 are eosinophilic myelocytes (1 is a very early one), showing a lack of azurophilic granules and an abundance of specific granules. In the eosinophil, these granules are large and acidophilic. The nucleus is pushed to one side and the chromatin is fairly condensed.
Cell 3 is a lymphocyte - intensely staining nucleus, little cytoplasm.
Cell 4 is a mature neutrophil. See the last group of slides if you don't know why.

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For more details, consult previous slides.

#2 Promyelocytes
#3,4 Neutrophilic metamyelocytes
#5 Late band neutrophil (almost mature)
#6 Mature neutrophil


Cell #1 is again the eosinophilic myelocyte.
Cell #7 is a red blood cell precursor, the basophilic erythroblast. More on that later. How about the rest of the field?

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#1 and 2 are late eosinophilic metamyelocytes/almost mature eosinophils. The nucleus is so indented that the lobes are almost apparent.
#3 is a late metamyelocyte/early band. It's nucleus isn't quite thin enough to be a band, but it's close.
#4,5, and 6 are all mature neutrophils.

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#1 is an early neutrophilic myelocyte.
#2 is an eosinophilic myelocyte - granules, flattened not indented nucleus.
#3 and 4 are neutrophilic metamyelocytes, with 4 being on the late myelocyte/early band cell border.
#5 is an almost mature eosinophil.
#6 is a mature neutrophil.
#7 is a normoblast.

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Cell 1 is a basophilic myelocyte. Basophils follow the same pattern of development as the other granulocytes, but as they are rare cells in the peripheral blood, developing basophils are hard to find. Therefore, you will not be asked to find them on your microscope slides. If you stumble across one, they are identifiable by their large, basophilic (navy blue with Wright's stain or Giemsa) specific granules.

#2 are eosinophilic myelocytes.
#3 are neutrophilic metamyelocytes (the member of the pair in the upper left corner, on the right side is a late meta/early band border cell).
#4 is a band cell.
#5 are polychromatophilic erythroblasts of the red cell lineage.
#6 is a mature neutrophil.

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Promyelocyte - large, loosely condensed nucleus, azurophilic granules prominent in cytoplasm.
Band Cell - curved, thin nucleus, neutrophil specific granules.
Eosinophil - bilobed nucleus, acidophilic, large, specific granules.
Lymphocyte - intensely staining nuclues with highly condensed chromatin, little cytoplasm.

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And now for some erythrocyte development. The series starts with the blast cell (#1). The cell shown could be the myeloblast of the white blood cell series or the proerythroblast of the red cell series - the distinction is very difficult.
The next cell in the lineage is the basophilic erythroblast (not shown). It has a strongly basophilic cytoplasm, more so than the blast and a condensed nucleus with no nucleoli.
Next is the polychromatophilic erythroblast (an early one #2). In this stage, the number of ribosomes and therefore the basophilia decreases. The cell stains purplish blue with Giemsa due to the mix of the basophilic ribosomes and acidophilic hemoglobin. The nucleus is even more condensed.
The next stage (#3) is the orthochromatophilic erythroblast or normoblast. The basophilia totally disappears, causing the cytoplasm to stain pink with Giemsa or Wright's. The nucleus is extruded during this stage.
The final stages will be discussed next slide.

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First, some housekeeping. The next stage after the normoblast is the reticulocyte. It looks like a typical mature RBC except that polyribosomes are still present and can be demonstrated with certain stains. This cell then loses its polyribosomes and becomes a mature erythrocyte.

#1 - Blast cell - large uncondensed nucleus, prominent nucleoli.
#2, 3 - Polychromatophilic erythroblasts - basophilia decreasing, condensed nucleus.
#4 - Normoblast - cytoplasm color matches that of the mature RBC but the nucleus is still present.
#5 - Dividing cell in the granulocyte lineage.
#6, 7 - Neutrophilic metamyelocytes (7 is early).
#8 - Mature neutrophil.

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The first frame, left hand side shows two normoblasts, one in the process of extruding its nucleus. Note the color of the normoblast cytoplasm matches that of the red cells in the field.
The next frame shows an early neutrophilic myelocyte (1-note the granules and flattened nucleus) surrounded by borderline late basophilic erthroblasts/early polychromatophilic erythroblasts (2-basophilia and condensed nucleus is evident).
The final frame shows a blast cell (1-loose chromatin, nucleoli visible, basophilia), a basophilic erythroblast (2-more condensed nucleus, increased basophilia), and polychromatophilic erythroblasts (3-decreased basophilia, but their color is not the same as the RBC's in the field, condensed nucleus).

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1_Early ProErythroblast
2 Polychromatic Erythroblast
3 Normoblast
4 Band cell (Late neutrophilic metamyelocite)
5 Nutrofill
6 Lymphocyte

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Plasma cells are found in the marrow as well as it is the site of B cell development. Note the clockface nucleus and the clear region underneath the nucleus.

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#1 is a plasma cell with clock face nucleus and a juxtanuclear clear region.
#2 is a mature neutrophil.
#3 are normoblasts.
#4 is a lymphocyte.
#5 is a neutrophilic metamyelocyte.
#6 - these three cells are not clearly identifiable.
#7 is a mature eosinophil.

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Acanthocyte

Acanthocytes are red blood cells with irregularly spaced projections. These projections vary in width but usually contain a rounded end. They may be found in abetalipoproteinemia and certain liver disorders.

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Atypical Lymphocyte

Atypical, or reactive, lymphocytes are lymphocytes that, as a result of antigen stimulation, have become quite large, sometimes more than 30 µm in diameter. The cells vary greatly in size and shape. The nucleus is less clumped than that of the normal lymphocyte. The shape of the nucleus ranges from elliptic to cleft to folded. The chromatin patterns appear similar to those of a blast and faintly stained multiple nucleoli are visible. The cytoplasm may range from large, deeply basophilic, and abundant to unevenly stained and granular. Causes of reactive lymphocytosis may be: ß-Streptococcus, cytomegalovirus, drugs, Epstein-Barr virus (infectious mononucleosis), syphilis, toxoplasmosis, vaccination, and viral hepatitis.

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Auer rod

Auer rods are elongated, bluish-red rods composed of fused lysosomal granules, seen in the cytoplasm of myeloblasts, promyelocytes and monoblasts and in patients with acute myelogenous leukemia.

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Basophilic stippling

Basophilic stippling appears as round, dark-blue granules in red blood cells on smears stained with supra vital stains such as brilliant cresyl blue. They may be observed in lead poisoning, exposure to some drugs, severe burns, anemias, or septicemia. The granules are precipitated ribosomes and mitochondria.

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Döhle bodies

Döhle bodies appear as a small, light blue-gray staining area in the cytoplasm of the neutrophil. They are found in poisoning, burns, infections, and following chemotherapy.

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Erythrocyte - polychromatophilic

Polychromatophilia may be defined as increased numbers of immature peripheral red blood cells that have a blue-gray tint on Wright-stained smears, indicating the presence of cytoplasmic RNA. These cells are usually larger than normal. Many of these cells prove to be reticulocytes when stained with supravital stains such as brilliant cresyl blue. They appear under conditions of accelerated red cell production.

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Echinocytes (crenated red blood cells)

Echinocytes are red blood cells with many blunt spicules, resulting from faulty drying of the blood smear or from exposure to hyperosmotic solutions. Pathological forms are associated with uremia. Echinocytes contain adequate hemoglobin and the spiny knobs are regularly dispersed over the cell surface, unlike those of acanthocytes.

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Giant platelets are platelets that are larger than 6.5 µm, or 75 to 100% the size of a normal red blood cell. A normal red cell is 6-8 µm in diameter. Normal platelets are approximately 1-4 µm, large platelets are approximately 4-6.5 µm.

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Howell-Jolly Bodies

Howell-Jolly bodies are spherical blue-black inclusions of red blood cells seen on Wright-stained smears. They are nuclear fragments of condensed DNA, 1 to 2m in diameter, normally removed by the spleen.

They are seen in severe hemolytic anemias, in patients with dysfunctional spleens or after splenectomy.

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Hypersegmented neutrophil

Hypersegmented neutrophils are neutrophils with 5 or more nuclear lobes. They are seen in disorders of nuclear maturation, such as the megaloblastic anemias.

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Metamyelocyte

Metamyelocytes have a cell diameter from 10 to 18 µm, and the nucleus to cytoplasm ratio is 1:1. Indentation of the nucleus begins at this stage, forming an outline that varies from slightly kidney shaped, to that of a broad V shape.

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Lymphoblast

Lymphoblasts are 12-20 µm in diameter with a round to oval nucleus, sometimes eccentric in location. The nucleus to cytoplasm ratio is about 4:1 and the periphery of both the nucleus and the cell may be irregular in outline.

The fine, highly dispersed nuclear chromatin stains a light reddish-purple, and one or two pale blue or colorless large nucleoli are visible. The cytoplasm is usually agranular and deeply to moderately basophilic, with marginal (peripheral) intensity a common characteristic.

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Monoblast

The monoblast is the first stage of monocyte-macrophage maturation. It is about 12 to 20 µm in diameter, has a nuclear to cytoplasm ration of 4:1 to 3:1, and, like most myeloid blasts, has a round to oval nucleus with fine, lightly dispersed chromatin.

From one to four nucleoli may be visible. The nucleus may be either central or eccentric and it may show evidence of indentation or folding. The cytoplasm is agranular, stains moderately to lightly basophilic, and often has an intensely stained periphery and a prominent perinuclear zone. Monoblasts never appear in the normal peripheral blood.

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Myelocyte

Myelocytes have a cell diameter from 10 to 18 µm. The nucleus to cytoplasm ratio is 1:1, and the oval or round nucleus is often eccentrically located. Chromatin is finely granulated in early myelocytes and more aggregated in later cells.

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Nucleated red blood cell

Nucleated red blood cells, (nrbcs or normoblasts), represent the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with responses to hemolytic crises, such as in megaloblastic anemia and iron deficiency anemia.

The average size of the normoblast is 7-12 µm in diameter. The cytoplasm is pink. The nucleus is pyknotic (a homogeneous blue-black mass with no structure).

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Myeloblast

The myeloblast is the first stage of the granulocytic series that is identifiable by light microscopy. It may be dificult to distinguish myeloblasts from other blasts in the peripheral blood unless one uses special stains or infers their identity from the presence of other immature cells of the same line.

A myeloblast can be distinguished from a promyelocyte by its lack of cytoplamic granulation. The nucleus is composed of very fine nonaggregated chromatin that stains light blue to reddish-purple with Wright's stain. Two to five distinct nucleoli are usually present. The nucleus is often bordered at one side by a distinct perinuclear zone.

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Pappenheimer bodies

appenheimer bodies are iron containing granules in red blood cells that are seen because the iron is aggregated with mitochondria and ribosomes. They appear as faint violet or magenta specks, often in small clusters, due to staining of the associated protein. They are associated with severe anemias and thalassemias.

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Teardrop cells (dacrocytes)

Teardrop shaped red blood cells are found in myelofibrosis and other myeloproliferative disorders, pernicious anemia, thalassemia, myeloid metaplasia, and some hemolytic anemias.

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Target cells

Target cells (codocytes) are erythrocytes with a central color spot in the area of pallor, resembling a target. They are seen in many hemolytic anemias, especially sickle cell, HbC disease, and thalassemia.

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Stomatocyte

Stomatocytes are red blood cells with an oval or rectangular area of central pallor, sometimes referred to as a "mouth". These cells have lost the indentation on one side and may be found in liver disease, electrolyte imbalance, and hereditary stomatocytosis.

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Spherocytes

Spherocytes are red blood cells that are almost spherical in shape. They have no area of central pallor like a normal red blood cell. Large spherocytes (macrospherocytes) are seen in hemolytic anemia. Small spherocytes (microspherocytes) are sometimes seen in severe burn cases.

A variety of spherical forms are seen in hereditary spherocytosis. The cells depicted in this image are from a patient with hereditary spherocytosis.

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Smudge or basket cell

Smudge cells or basket cells are leukocytes that have been damaged during preparation of the peripheral blood smear. This usually occurs due to the fragility of the cell. They are usually seen in chronic lymphocytic leukemia (CLL).

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Sickle cells

Sickle cells are red blood cells that have become crescent shaped. When a person with sickle cell anemia is exposed to dehydration, infection, or low oxygen supply, their fragile red blood cells form liquid crystals and assume a crescent shape causing red cell destruction and thickening of the blood. Since the life span of the red blood cell is shortened, there is a temporary depression of red cell production in the bone marrow, and a subsequent fall in hemoglobin (and therefore the resultant anemia).

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Schüffner's granules

Schüffner's granules may be found in cases of Plasmodium vivax. These granules appear as orange to pink colored stippling throughout the red blood cell. They may not be visible when normal staining times are used. To detect these granules, the smears should be allowed to stain for three hours.

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Schistocyte

Schistocytes are red blood cell fragments that result from membrane damage encountered during passage through vessels. They occur in microangiopathic hemolytic anemia, severe burns, uremia, and hemolytic anemias cause by physical agents, as in disseminated intravascular coagulation (DIC). They are sometimes referred to as "bite cells".

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Rouleaux

Rouleaux formation occurs when red blood cells form stacks or rolls. This is due to either an artifact (such as a result of not preparing the blood smear soon enough after placing the blood on the slide), or it may be due to the presence of high concentrations of abnormal globulins or fibrinogen. This formation of the red blood cells is found in multiple myeloma and macroglobulinemia

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Promyelocyte

Promyelocytes are the second largest stage in the granulocytic series. The large, reddish-purple granules that characterize promyelocytes are nonspecific in that they are shared by the other granulocytes (eosinophils and basophils). These granules are peroxidase positive, and a lipid component reacts with Sudan black stain, providing a second cytochemical reaction for the identification of large mononuclear cells in blood and bone marrow smears. The cell size, 12 to 20 µm, is the same as that of a myeloblast, but the nucleus to cytoplasm ratio is less, usually from 3:1 to 2:1. The chromatin is still fine, but some aggregation is evident. One to three nucleoli are also visible, although these can be obscured by heavy granulation.

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Plasma cell

A plasma cell is a mature B lymphocyte that is specialized for antibody (immunoglobulin) production. Plasma cells are rarely found in the peripheral blood. They comprise from 0.2% to 2.8% of the bone marrow white cell count.

Mature plasma cells are often oval or fan shaped, measuring 8-15 µm. The nucleus is eccentric and oval in shape. The nucleus to cytoplasm ratio is typically 2:1 to 1:1. The nucleus may be bilobed or multilobed, especially in patients with lymphoid blood dyscrasias. The perinuclear zone is very distinct, appearing white in the deeply basophilic cytoplasm. Nuclear chromatin is condensed and very patchy, appearing as dark blocks on a reddish-purple background. The cytoplasm stains deep blue to gray blue, depending on the stain and the ribosomal content of the individual cell. Plasma cells are seen in multiple myeloma, plasma cell leukemia, Waldenström's macroglobulinemia, and MGUS (monoclonal gammopathy of uncertain significance. The cells depicted in this image are from a patient with plasma cell leukemia.

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Platelet satellitosis

Platelet satellitosis, (platelets encircling a neutrophil) occurs when a patient has a serum factor that reacts to the anticoagulant EDTA.

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Parasites

The most common parasites encountered in the peripheral blood include malaria and babesia. Malaria is discussed in detail on the malaria link.

Babesia are small ringlike protozoa within erythrocytes that resemble the ring stages of falciparum malaria. Most infections result from Babesia microti which is transmitted from wild feral deer mice to humans by the tick Ixodes dammini. It occurs in Nantucket Island, on coastal regions of the northeastern US, and in California. It has been found in France, Ireland, Scotland, and other European countries.

The diagnosis of babesiosis can be made by demonstration of the ring-shaped parasites on Wright-Giemsa stained smears. Babesia are tiny rings with a minute chromatin dot and a minimal amount of cytoplasm. They may be round, oval, elongated, or ameboid. One or two chromatin dots, which stain dark purple, may be observed. More than one ring can be seen in an RBC. Tetrad forms may be noted and aid in positively identifying babesia.

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Toxic granulation

Toxic granulation appears as dark blue-black granules in the cytoplasm of neutrophils. These granules are thought to be primary granules.

Artifactual heavy granulation caused by poor staining is seen evenly spread throughout each cell and in all granulocytes, whereas toxic granulation is unevenly spread throughout the cytoplasm of certain cells. Large amounts of toxic granulation can give the neutrophil a bluish appearance.Toxic granulation is a stress response to acute infections, burns, and drug poisoning.

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Bacteria

The image below illustrates a neutrophil with bacteria (Gram positive cocci). The major function of the neutrophil is to stop or retard the action of foreign matter or infectious agents. The neutrophil accomplishes this by moving to the area of inflammation or infection, phagocytizing (ingesting) the foreign material, and killing and digesting the material. Bacterial sepsis can result in a leukemoid reaction, involving white cell counts of 100,000 X 106/L (normal WBC=4,500 to 11,000 X 106/L), the presence of myelocytes, and the appearance of toxic granulation.This image was taken from a patient with Streptococcus pnemoniae infection.

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Pelger-Huët Anomaly

Pelger-Huët anomaly is a benign hereditary condition characterized by decreased segmentation in the neutrophils. These neutrophils usually contain two lobes, but appear to function normally.

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Yeast

The image below illustrates a neutrophil with intracellular yeast. The major function of the neutrophil is to stop or retard the action of foreign matter or infectious agents. The neutrophil accomplishes this by moving to the area of inflammation or infection, phagocytizing (ingesting) the foreign material (in this case, the yeast), and killing and digesting the material.

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Chronic granulocytic leukemia (CGL)

Chronic granulocytic leukemia or chronic myelogenous leukemia can occur at any age, but is most common after the age of 45 years. Weight loss and fatigue are often the initial symptoms. There is usually massive spleen enlargement, which may cause left upper abdominal pain. There is anemia, markedly elevated levels of leukocytes, thrombocytosis, eosinophilia, basophilia, and a predominance of myelocytes in the peripheral blood. Myeloblasts constitute fewer than 10% of circulating leukocytes. Occasional nucleated red blood cells are seen. The cells depicted in the image below are two myeloblasts and a hypersegmented neutrophil.

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Malaria

Malaria is a disease caused by the parasite Plasmodium. The four species most commonly found in man are vivax, malariae, falciparum, and ovale.

"Malaria is mainly transmitted from person to person through the bite of the female Anopheles mosquito. Other means of transmission are through the use of contaminated needles, by congenital means, and through blood transfusions.

When the infected Anopheles mosquito bites a human, sporozoites are injected into the peripheral blood of the individual. The sporozoites then invade the liver. When the red blood cell has been penetrated by the merozoite, the parasite develops into the trophozoite ring form and thence to a mature schizont. The merozoites rupture from the mature schizonts and penetrate other red blood cells. Fever and chills are associated with the rupture of the red blood cells."

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Acute myelocytic leukemia (AML)

Acute myelocytic leukemia (AML), is the most common leukemia in children less than 1 year of age. It is rare in older children and adolescents, but a second peak of incidence occurs among adults 40 years of age. The patient usually has an elevated white blood cell count, and myeloblasts are present.

Anemia, thrombocytopenia, and neutropenia give rise to the clinical findings of pallor, bruising and bleeding, fever with infections, and fatigue. Bone pain and joint pain are seen as the first symptoms in 25% of patients. Enlarged spleen is seen in 50% of all AML patients, but lymph node enlargement is rare. The cell depicted in the image below is a myeloblast.

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Acute lymphocytic leukemia (ALL)

Acute lymphocytic leukemia (ALL) usually strikes children between the ages of 2 to 10. A second peak in incidence is seen in elderly patients.

Only half of all patients with ALL have increased leukocytes and may not have lymphoblasts in their peripheral blood. Neutropenia, thrombocytopenia, and anemia are usually present. Patients have symptoms of fatigue, fever and bleeding. There is often lymph node enlargement. Enlargement of the spleen and of the liver may be seen. The cells depicted in the image below are two lymphoblasts and a neutrophil.

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Chronic lymphocytic leukemia (CLL)

Chronic lymphocytic leukemia is the most common type of leukemia and usually occurs in older patients; it is rare in patients less than 40 years of age. The disease is usually discovered when other medical problems are present. Weakness, fatigue, and weight loss are usually seen. The malignant cell in CLL is usually a small, mature-appearing lymphocyte.

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Hairy cell leukemia

Hairy cell leukemia, or leukemic reticuloendotheliosis, is a rare malignant disorder. It usually occurs in middle-aged patients over 50. The first symptoms of disease include weakness and lethargy. Enlarged spleen occurs in 80% of patients.

Hairy cells are characterized by their fine, irregular pseudopods and immature nuclear features. Bone marrow aspiration is often unsuccessful because of complete infiltration by hairy cells, resulting in a dispersed spongy web of cells in an increased meshwork of reticulin fiber.

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Band neutrophil

Band neutrophils comprise approximately 1 to 3% of the peripheral leukocytes. They are usually 9 to 15 µm in diameter. The nucleus forms a "U" or curled rod prior to segmentation. The chromatin pattern is coarse and clumped. The cytoplasm is moderate to abundant with a few nonspecific granules and many specific granules.

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Basophil

Basophils are granulocytes that contain purple-blue granules that contain heparin and vasoactive compounds. They comprise approximately 0.5% of the total leukocyte count. Basophils participate in immediate hypersensitivity reactions, such as allergic reactions to wasp stings, and are also involved in some delayed hypersensitivity reactions. Basophils are the smallest circulating granulocytes, averaging 10 to 15 µm in diameter. The nucleus to cytoplasm ratio is about 1:1, and the nucleus is often unsegmented or bilobed, rarely with three or four lobes. The chromatin pattern is coarse and patchy, staining a deep blue to reddish-purple. The cytoplasm is a homogenous pale blue, but this is often obscured by the large dark granules.

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Eosinophil

Eosinophils are the mature granulocytes that respond to parasitic infections and allergic conditions. Eosinophils comprise about 1 to 4% of the peripheral leukocytes. They are usually 9 to 15 µm in diameter. Granules stain a bright reddish-orange with Wright's or Giemsa stains. The nucleus contains one to three lobes. The chromatin pattern is coarse and clumped. The cytoplasm is abundant with a full complement of bright reddish-orange specific granules.

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Platelets

Platelets are the cytoplasmic fragments of megakaryocytes, circulating as small discs in the peripheral blood. They are responsible for hemostasis (the stoppage of bleeding) and maintaining the endothelial lining of the blood vessels. During hemostasis, platelets clump together and adhere to the injured vessel in this area to form a plug and further inhibit bleeding. Platelets average 1 to 4 µm in diameter. The cytoplasm stains light blue to purple, and is very granular. There is no nucleus present. Normal blood concentrations range from 130,000 to 450,000/µL.

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IRON DEFICIENCY ANEMIA]. Iron deficiency anemia (IDA) is the most common form of anemia worldwide and more commonly seen in certain patient populations including children, young adolescent females, menstruating females, and older males and females with dietary deficiencies. Morphologically IDA is characterized by variable degrees of microcytosis (MCV < 80 fl) and hypochromasia (MCHC < 32 g/dl) which results in widening of the central pallor accounting for >1/3 of the total RBC diameter (arrowhead). The variation in cell size (anisocytosis) results in a higher RDW reflecting the fact that iron deficiency is an acquired disorder with different levels of hemoglobin production in red cells.

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[IRON DEFICIENCY ANEMIA]. The reduced red cell size is best appreciated in comparison with a small lymphocyte (right arrow). The nucleus of a small lymphocyte is about the size of a normal RBC. In IDA most red cells are smaller than the nucleus of a small lymphocyte (arrowhead). Although morphology is often very characteristic of iron deficiency anemia a definitive diagnosis requires laboratory tests including complete/full blood count (CBC/FBC) which shows decreased MCV, decreased MCHC, and high RDW. Additional tests may also show decreased levels of serum ferritin, low serum iron, reduced transferring saturation, increased serum total iron binding capacity, increased soluble transferring receptor in serum and increased RBC protoporphyrin levels may also be helpful in selected cases.

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[IRON DEFICIENCY ANEMIA]. In severe iron deficiency characteristic morphologic changes include microcytosis (low MCV), hypochromasia (low MCHC), anisocytosis (high RDW), and poikilocytosis (abnormal shaped RBCs) with elliptocytes (arrowheads) and target cells. Reticulocytes are decreased. Other microcytic anemias such as thalassemia, sideroblastic anemia, anemia of chronic diseases and certain hemoglobin disorders should be excluded based on clinical history and laboratory tests.