HematologyOutlines

Also known as Spur Cell is an RBC with irregular thorn-like projections. Looks like "Cowboy Boot Spurs". These RBCs may be seen in some peripheral smears due to artifacts or may be associated with certain conditions including Abetalipoproteinemia, Liver disease, Malnutrition, Hypothyroidism, Asplenia, and McLeod Phenotype of Kell blood group, etc.

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Refers to the variation in "size" of red blood cells. Laboratory value that correlates with anisocytosis is an elevated RDW.

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Type of white blood cell and more specifically a type of lymphocyte which produces antibodies (immunoglobulins). B-cells (like other hematopoietic cells) originate in the marrow and start maturation in the bone marrow and complete their maturation process in germinal center of secondary follicles within secondary lymphoid tissues/organs such as lymph nodes, mucosa associated lymphoid tissue (MALT), or spleen. Remember B-cell for Bone marrow and T-cell for Thymus (B-cells start maturation in Bone marrow while T-cells mature in the Thymus.

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Refers to band form of Neutrophil. A maturing neutrophil that precedes the segmented neutrophils (PMNs) in the granulocytic maturation scheme. Increased numbers of Bands may be indicative of an underlying infection (especially bacterial).

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Type of white blood cell and more specifically granulocyte that maybe elevated in certain conditions such as but not limited to allergic reactions or CML.

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Special fluid that is within vessels and is comprised of the cellular components (e.g. red blood cells, white blood cells and platelets) and plasma with proteins (e.g. clotting factors, vW factor, etc.).

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Blue-Gray cytoplasmic inclusions (remnants of Rough ER) that may be seen in neutrophils. Increased numbers may be indicative of an underlying inflammatory condition and/or infection. If Dohle bodies are accompanied by giant platelets, it may be due to May Hegglin anomaly.

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Oval shaped RBCs (AKA ovalocytes). Can be seen in variety of conditions including iron deficiency anemia and hereditary elliptocytosis.

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A type of WBC seen in peripheral blood and tissue. It belongs to the myeloid lineage and more specifically a subtype of granulocyte with bright eosinophilic (red) granules containing Major Basic Protein, histamine, and plasminogen. Increased numbers of eosinophils in blood can be due to many things (remember the major classes for most differential diagnosis include an underlying Infection, Malignancy, autoimmune, trauma, congenital, drug-induced or idiopathic). Increased eosinophils may be due to an infection (e.g. tissue invasive parasites), Malignancy (e.g. Hodgkin Lymphoma, Carcinoma or Chronic Eosinophilic Leukemia), Autoimmune, Drug-induced (e.g. certain antibiotics, etc.), or idiopathic.

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Another name for Red blood Cell (RBC). Belongs to the myeloid cell lineage. RBCs main role is to carry and deliver oxygen through hemoglobin.

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AKA schistocytes and helmet cells are irregularly shaped assymetrical fragments of RBCs that may have several morphologic forms. It is usually the result of mechanical disruption of the RBCs. They can be generated by getting stuck to fibrin strands within the vasculature secondary to an underlying Microangiopathic hemolytic anemia such as HUS, TTP and DIC or broken up by a mechanical heart valve).

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Very large platelets. Usually equal to or larger than the size of a normal RBC. Increased numbers in peripheral blood smears may be indicative of an underlying marrow or myeloid disorder.

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Belongs to the myeloid lineage. There are three different types: neutrophils (with neutral staining granules), eosinophils (with Eosinophilic or red staining granules), and basophils (with basophilic or blue/purple staining granules).

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AKA schistocyte is an irregularly shaped asymmetrical fragment of RBC that may have several morphologic forms. It is usually the result of mechanical disruption of the RBCs. They can be generated by getting stuck to fibrin strands within the vasculature secondary to an underlying Microangiopathic hemolytic anemia such as HUS, TTP and DIC or broken up by a mechanical heart valve).

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These are basophilic nuclear remnants (fragments of chromatin/DNA) in RBCs. Mostly seen in post-splenectomy patients or those with asplenia. Commonly seen in adults with sickle cell disease (Hb SS) since these patients have undergone autosplenectomy by the time they reach their adulthood. Remember as opposed to "HEinz" bodies which start with "HE" and stands for hemoglobin, Howell Jolly Bodies don't start with "HE" and are rather DNA or nuclear remnants.

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These are neutrophils with more than 5 lobes (so 6 or more lobes. Recall, normal neutrophils should have 3-5 lobes). hypersegmented neutrophils are most commonly associated with B12 or folate deficiency (two common causes of a macrocytic anemia).

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Also known as LGLs, these are T-lymphocytes with an increased amount of cytoplasm and multiple small red cytoplasmic granules. Increased numbers could be seen in reactive conditions (such as infections) or an indolent neoplastic process such as the T-cell Leukemia known as T-LGL leukemia.

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Usually refers to seeing less mature cells of a certain lineage. Commonly refers to seeing an increased amount of less mature myeloid (granulocytic) precursors such as myelocytes, metamyelocytes and bands in the blood or bone marrow.

Means "White cells" and refers to the White blood Cells (WBCs) which include granulocytes (Neutrophil, Eosinophil, Basophil), monocytes, and lymphocytes and their precursors. The leukocyte precursors (e.g. promyelocyte, myelocyte, metamyelocyte) are usually seen in the bone marrow and absent in blood of normal individuals.

Refers to the presence of white blood cell precursors and nucleated RBCs in the peripheral blood. This may be due to an underlying marrow infiltrative process, severe infection or severe hemolysis.

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A type of leukocyte or WBC (second most prevalent WBC in a normal peripheral blood. Most prevalent is neutrophils followed by lymphocytes followed by monocytes, followed by eosinophils and ultimately basophils which are rarely seen). The three main types of lymphocytes include B-cells, T-cells and NK-cells.

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Usually refers to macrocytic (larger) RBCs as seen in macrocytic anemias. Characterized by an elevated MCV (larger RBCs with MCV >100fL). On blood smears, macrocytic red cells are larger than a lymphocyte nucleus. Common causes include B12 or folate deficiency, Liver disease, increased reticulocytes, drug-induced (e.g. methotrexate), and MDS.

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Due to Myosin Heavy Chain 9 (MYH-9) mutation. Patients usually show Dohle-like bodies in their neutrophils along with giant platelets in peripheral blood.

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Usually refers to microcytic (small) RBCs that are seen in microcytic anemia. These are anemias with small RBCs (MCV of <80fL). The Meumonic for Microcytic anemia is "Puny TICS". Both Puny and TICS are small things. Hence, small RBCs with low MCV. P in Puny for Pyridoxine deficiency, T for thalassemia, I for Iron deficiency, C for Chronic disease anemia (sometimes but most are normocytic) and S for sideroblastic anemia (such as in Pb poisoning or congenital sideroblastic anemia).

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Small round RBCs with no central pallor that may be seen in in blood smears from patients with immune-mediated hemolytic anemia, burn injuries, and hereditary spherocytosis.

A type of white blood cell (myeloid lineage). These are usually the largest circulating cells in the blood and usually 2-3 times the size of a mature lymphocyte. Their nucleus is usually folded, and there is a large amount of light blue cytoplasm and commonly show cytoplasmic vacoules. monocytes that leave the blood and enter tissue are called macrophages.

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Also known as PMN (for polymorphonuclear), it belongs to the myeloid (granulocytic) cell lineage. neutrophils usually increase in blood secondary to infection (esp. bacterial). As opposed to eosinophils and basophils, the granules in neutrophils are neutral (light pink) in color.

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These are normal appearing mature RBCs and can be seen in normal individuals or those with certain anemias. As opposed to the immature Erythroid precursosrs which are nucleated, the mature RBCs lack a nucleus and have a central pallor that is usually 1/3 of it's diameter. The main function of the RBC is to carry oxygen through it's hemoglobin molecules.

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This refers to "normal size" mature RBCs or anemias with normocytic appearance (MCV 80-100 which is the normal range). These anemias include but are not limited to Hemolytic anemia, sickle cell anemia, and Anemia of Chronic disease.

Also sometimes referred to as elliptocytes are RBCs with an elongated or oval shape and may be secondary to hereditary elliptocytosis or iron deficiency anemia to name a few.

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Dense, blue-purple granules of iron found in the periphery of the cytoplasm of an RBC. Most commonly, they are associated with splenectomy, either surgical or as a complication of sickle cell anemia. They also can be seen in smears from patients with sideroblastic anemia, and hemolytic anemias. In contrast to Howell-Jolly (HJ) bodies that are a single, very round red cell inclusions, pappenheimer bodies are smaller, more irregular in outline, and often are multiple per red cell.

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An rare inherited condition due to lamin B receptor mutation in which most of the peripheral blood neutrophils present with bilobed nuclei connected with a thin filament of chromatin (similar to the bilobed nuclei noted on normal mature eosinophils but without the eosinophilic granules). In heterozygous individuals these neutrophils appear to maintain their function, and most of these individuals are asymptomatic (hence the term anomaly rather than disease).

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Cellular fragments (2-3 um in diameter which correlates to about 1/3 to 1/2 the size of a RBC) released from megakaryocytes into the blood and involved in hemostasis.

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The presence in the blood of erythrocytes showing abnormal variation in "shape". Mnemonic is when compared to anisocytosis. Both the words "Shape" and "poikilocytosis" contain a "P". Therefore Poikilocytosis has to do with RBC Shape variation while Anisocytosis (No "P" in the word) has to do with variation of "size" (No "P" in the word).

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Usually refers to the polychromatophilic RBC which is less mature non-nucleated red blood cell with a light basophilic (light blue-purple) color on peripheral smear which is due to the presence of cytoplasmic RNA. Increased numbers may be seen in certain anemias such as hemolytic anemia in which earlier RBCs are being released by the reactive bone marrow in response to the anemia with the earlier release of these less mature RBCs into circulation. Special stain can highlight the RNA molecules in these cells and on the special stain these cell are known as reticulocytes.

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Pseudo-thrombocytopenia is an artifactual clumping of platelets that can occur after exposure to EDTA. The clumping occurs only in the test tube with EDTA and may be associated with an antibody that reacts to platelet antigens only in the presence of EDTA. Citrated blood can be used to get an accurate platelet count when EDTA causes this problem.

They used to be called atypical lymphocytes. These large lymphocytes may be increased in the peripheral blood smear in certain inflammatory conditions such as an underlying viral infection (e.g. EBV induced mononucleosis, the lymphocytes look so large that they start resembling monocytes). They usually have increased amount of cytoplasm which wraps or hugs the surrounding RBCs. reactive lymphocytes are typically CD8+ T-cells.

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Also called RBC or erythrocyte, are the most common type of blood cell in the body. It's role is to deliver oxygen via the hemoglobin molecule to various tissues and organs.

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These are irregularly shaped assymetrical fragmented RBCs that may have several morphologic forms (e.g. Helmet cells, etc.). It is usually the result of mechanical disruption of the RBCs and many of which are generated by getting stuck to fibrin strands within the vessel wall (intravascular destruction) which may be secondary to a Microangiopathic hemolytic anemia such as HUS, TTP and DIC or a fibrin-independent destructive path such as being broken up by a mechanical heart valve.

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Sphere shaped erythrocytes (RBCs) with reduced membrane and diameter which can be due to hereditary spherocytosis or autoimmune hemolytic anemia when increased numbers are noted in blood.

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Also known as acanthocyte is a RBC with irregular thorn-like projections. Looks like "Cowboy Boot Spurs". These RBCs may be associated with many conditions including but not limited to abetalipoproteinemia, liver disease, malnutrition, asplenia, and Mcleod phenotype blood group.

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Stomatocytes are erythrocytes with a loosely folded, mouth-like pale area across the cell. They can be seen in hereditary stomatocytosis, liver disease, Rh null phenotypes, and Tangier's disease.

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T-cells (AKA T-lymphocyte) are white blood cells involved in cell-mediated immunity along with other cells such as NK cells, etc. T-cell maturation (positive and negative selection) takes place within the Thymus (Remember T for T-cell and T for Thymus). Main subtypes of T-cells include, T-helper cells (CD4+) and cytotoxic T-cells (CD8+).

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Target cells are RBCs that resemble a bull's-eye; commonly seen in patients with thalassemia, certain hemoglobinopaties (e.g. Hb C disease), or even liver disease but can also be due to an artifact seen on certain peripheral blood smears secondary to slow drying of blood or excess EDTA.

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Teardrop cells (dacrocytes) are RBCs that resemble a teardrop in the peripheral blood smear. They are often seen in people with an underlying myelofibrosis or other marrow space occupying disorders.

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Toxic granules are dark blue/purple granules seen within the cytoplasm of neutrophils and typically associated with an underlying bacterial infection or sepsis. Toxic granules may be accompanied by toxic vacuoles.

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Toxic vacuoles are typically associated with an underlying inflammatory reaction and commonly associated with infections. The cytoplasm of these neutrophils commonly also displays toxic granules and sometimes Dohle_bodies.

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Cells that contain vacuoles within the cytoplasm. The vacuoles are typically thought to be of lysosomal origin as seen in mature circulating monocytes in blood. Cells that typically have vacuoles include but are not limited to neutrophils, monocytes, monoblasts, abnormal erythroid precursors (e.g. Erythroid Leukemia), and Burkitt Lymphoma's leukemic phase.

Also known as WBC which are the nucleated cells noted in the peripheral blood as part of a CBC and include neutrophils, lymphocytes, monocytes, eosinophils, and basophils (in order of prevalence).

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Peripheral Blood Components