Review of Terms

Reticulocyte index	= Retic x (Pt HCT/Norm HCT)	The Reticulocyte production index (RPI, also called a corrected reticulocyte count) is a calculated value used in the diagnosis of anemia. This calculation is necessary because the raw reticulocyte count is misleading in anemic patients. The problem arises because the reticulocyte count is not really a count but rather a percentage: it reports the number of reticulocytes as a percentage of the number of red blood cells. In anemia, the patient's red blood cells are depleted, creating an erroneously elevated reticulocyte count.
Reticulocyte	Reticulocytes are newly formed erythrocytes. When stained supravitally with new methylene blue, they contain a blue reticular (RNA) network.  These cells appear as macrocytes with diffuse cytoplasmic basophilia (polychromasia) when stained with Wright stain (next image). The normal reticulocyte count:  0.5-2.5%.
Polychromatic Red Cell	Polychromatic red cells are somewhat larger than normal and have a faint bluish or grayish-pink color.  The color is due to a small amount of RNA.  Significantly higher percentage reflects increased production - same significance as reticulocyte
Normal red cell morphology	Note the relative uniformity of size (7-8 microns; approximately the same size as the nucleus of a small lymphocyte) and shape of the red cells and the normal hemoglobin content as evidenced by the central area occupying approximately 1/3 of the cell. Life span 100-120 days
Platelets	Normal platelet size = 1-2 microns and 7-9fL (about 1/7 to 1/5 size of a RBC) Average lifespan 7-10 days Here we see platelet satellitosis, (platelets encircling a neutrophil) occurs when a patient has a serum factor that reacts to the anticoagulant EDTA.
Target Cells	surface/volume ratio Significant numbers of target cells occur in three situations: (1) hepatobiliary disease (increased cholesterol accumulating in cell membrane); (2) hemoglobinopathies C, D, and E; (3) thalassemias
Hemoglobin C disease	Homozygous hemoglobin C disease. In this condition there are many target cells as well as spherocytes. The target cell in stained preparations is a cell with hemoglobin on the edge, a light area, and more hemoglobin in the center. With scanning electron microscopy it appears to be bell-shaped. Target cells may be seen in small numbers in any type of anemia, but are seen in greatest numbers in liver disease, thalassemia, and hemoglobinopathies. They also may be artifactual due to slight pH changes in the glass slide. If they are seen only one area on the slide they are probably not true target cells but represent artifacts.
Spherocytes	surface/volume ratio Because of their spherical shape, which is due at least in part to loss of membrane area, they are more susceptible to osmotic stress as measured by the osmotic fragility test.
Acanthocyte	(spurr cell) 5-10 spicules	Red cells with multiple irregularly distributed, thorn-like spicules often with drumstick ends. -Found in association with hereditary abetalipoprotenemia but also seen in severe liver disease, hepatorenal failure, anorexia nervosa and in chronic starvation. -A small number of acanthocytes may be found in forms of hemolytic anemia (especially post splenectomy).
Echinocyte	(Burr cell) 10-30 spicules evenly distributed	Reflect damage to the normal cell membrane by various lytics–eg, saponin, bile salts, ionic detergents, lecithin; slow drying; aged blood; rarely, echinocytes reflect disease–eg, uremia or pyruvate kinase deficiency.
Pynoknocytes
Schistocytes	· Schistocytes are fragmented red cells and are seen in a variety of shapes and sizes.  Schistocytes are associated with: -Thrombotic thrombocytopenic purpura (TTP) -Disseminated intravascular coagulation (DIC) -Microangiopathic hemolytic anemia, -Uremia -Carcinoma
Elliptocytes	Elliptocytes are red blood cells that are oval or cigar shaped. They may be found in various anemias, but are found in large amounts in hereditary elliptocytosis
Tear Drop Cells	These poikilocytes are most numerous in myelofibrosis with myeloid metaplasia (MMM) and bone marrow infiltration. They may occur in small numbers in nuclear or cytoplasmic maturation defects. In MMM the spleen is responsible for producing this shape change. Following splenectomy, tear‑drop cells disappear. Whether these cells are produced within the spleen result from some change induced during circulation.
Stomatocytes
Kleihauer Betke Technique	Acid elution method for detecting HbF in maternal circulation
Phagophagia	Abnormal urge to eat large quantities of ice due to iron deficiency.
Geophagia	Abnormal urge to eat sand/earth due to iron deficiency.
Kelley Paterson Syndrome	Esophageal Webs and Fe Deficiency
Imerslund Grasbeck Syndrome		· A familial syndrome characterized by juvenile pernicious anaemia caused by selective malabsorption of vitamin B12 caused by a defect in the vitamin B12/intrinsic factor receptor. · Both sexes affected; onset most commonly in second year of life. · Principal symptoms include fatigue; weakness; pallor, gastrointestinal disorders with diarrhoea and vomiting, glossitis, jaundice, heart murmur and proteinuria. Urinary tract abnormalities are frequent, e.g. double ureters. · Inheritance is autosomal recessive
Donath Landsteiner antibody	Diagnosis of paroxysmal cold haemoglobinuria. This rare disorder may occur in syphilis and after viral infections in children.	· Collection by laboratory staff into 2 plain tubes, one at 37°C and one at 4°C. · Supernatant serum examined for evidence of red cell lysis, comparing a tube incubated at 4°C then 37°C with a tube maintained at 37°C. · The Donath Landsteiner antibody is an IgG autoantibody that binds to red cells in the cold and fixes complement; lysis occurs when cells are warmed to 37°C.
Basophilic stippling of erythrocytes (BSE)	Represents the spontaneous aggregation of ribosomal RNA in the cytoplasm of erythrocytes. These aggregates stain are visible, with routine hematology stains. is seen in lead poisoning, thalassemias, and other anemias.
Howell-Jolly bodies	Spherical blue bodies (Wright Stain) within or on erythrocytes: nuclear (DNA) debris. Associated with hyposplenism and pernicious anemia.
Heinz body	· Fresh blood incubated with supravital stain and examined by microscopy for presence of stained inclusions close to the red cell membrane (Heinz bodies). · Investigation of haemolysis (when fragmented spherocytes seen on blood film) or with history of exposure to oxidant chemical or drug. · Heinz bodies are denatured globin, and represent the end-product of oxidative degradation of haemoglobin. · Heinz bodies may be detected post-splenectomy, with oxidative haemolysis (in normals, but particularly in patients with G-6-PD deficiency) and in patients with unstable haemoglobinopathies.
G6PD Deficiency	· Mild in black Africans · G6PD during acute hemolysis may be falsely high. · Bite cell in acute hemolysis
G6PD Deficiency	· Blister call in acute hemolysis
Sickle Cell Anemia	Sickle cell anemia (black arrow indicates a nucleated red cell, white arrow a sickle cell, and arrowhead a boat-shaped cell).
Hereditary pyropoikilocytosis.
Microangiopathic hemolytic anemia	resulting from cyclosporine therapy.
Type I congenital dyserythropoietic anemia.
Sickle cell–hemoglobin C disease	arrows indicate SC poikilocytes
Megaloblastic Anemia	Megaloblastic anemias, whether due to vitamin B12 deficiency or folic acid deficiency, present with almost identical morphologic blood and bone marrow changes.  Anemia is normochromic and macrocytic - MCV sometimes reaching as high as 150 cubic microns (μ^3).  Presence of macro-ovalocytes is considered quite characteristic of megaloblastic anemia. The reticulocyte count is usually decreased despite marked anemia.  The so-called right shift of neutrophils (hypersegmented - six or more lobes) typify megaloblastic anemia.  Thrombocytopenia is also not uncommon.  The bone marrow is hyper-cellular, reflecting predominately the megaloblastic hyperplasia.  The megaloblastic changes are noted in all three lines, i.e. red cells, white cells, and platelet precursors within the marrow. Serum B12 and/or folic acid levels and the red cell folate concentration are decreased.  Serum lactic dehydrogenase concentration is high.
Microcytic Hypochromic Anemia	A microcytic, hypochromic anemia characterized by decreased hemoglobin, decreased hematocrit, and decreased red cell indices (MCV, MCH and MCHC) is the hallmark of iron deficiency anemia.  A moderate degree of anisocytosis (variation in size), moderate to marked poikilocytosis (variation in shape) and significant elliptocytosis frequently accompany moderate and severe degrees of iron deficiency anemia.  The leukocyte count is generally normal, whereas the platelet count is frequently increased.  The reticulocyte count may be normal or slightly decreased - rarely if ever increased.  The bone marrow is normoblastic and depleted of stainable iron.  Additional features of diagnostic importance are low serum ferritin, low serum iron, and increased total iron binding capacity (TIBC).
Myeloblast Blast=early	A myeloblast is a large cell, 12-20 microns in diameter, with a nucleus that takes up most of the cell. Nuclear chromatin is fine, with little condensation and fairly homogenous in appearance. Nucleoli may vary in number and are apt to be large. The scanty cytoplasm is blue without granules.
Promyelocyte Pro=before	A promyelocyte may be the same size as the myeloblast or even larger. Unlike the myeloblast, the promyelocyte's cytoplasm contains large black or purple granules. Nucleoli may be present.
Myelocyte	The myelocyte is smaller than the myeloblast or the promyelocyte. Unlike the myeloblast and promyelocyte, the myelocyte's cytoplasm contains specific granules, i.e. brick-red (eosinophils), large, blue-black granules (basophils), and lilac granules (neutrophils). The nucleus still has a round or oval shape and no nucleoli are present.  Myelocytes are not seen on a normal peripheral blood smear.
Metamyelocyte Meta=after	Metamyelocytes (Juvenile) are smaller than the myelocytes.  There is more marked clumping of the nuclear chromatin so that the nucleus becomes much denser, takes up less than half the cell volume, and is indented (kidney-shaped).
Band (stab)	The band (stab) is similar to the metamyelocyte but the band is smaller and has a horseshoe-shaped nucleus.  The cytoplasm may contain fine lilac granules (neutrophilic), brick-red granules (eosinophilic) or large blue-black granules (basophilic).  Bands normally account for 0-5% of the total leukocyte count in circulating blood of the adult.
Segmented Neutrophil	A segmented neutrophil (poly) is approximately 12-14 microns in diameter.  This is the final stage of granulocytic development. Normal polys generally have two to five lobes.  Hypersegmented polys, containing six or more lobes, are characteristically seen in megaloblastic anemias.  Polys normally account for 45-75% of a normal differential in an adult.
Monocyte	A monocyte has blue-gray cytoplasm and a lobulated nucleus. It's distinguished from other leukocytes by the folding-over of the nuclear lobe (fetal-shaped). 4-11% in a normal blood differential.
Basophil	Basophils are present in small numbers (0-3%) in a normal blood smear.  Dark coarse granules and indistinct nucleus are characteristic.  The basophil is a source of histamine and involved with allergic and inflammatory/immune responses.  Increased numbers are seen in myeloproliferative disorders, e.g. chronic myelogenous leukemia and polycythemia vera.
Eosinophil	Eosinophils are characterized by the presence of numerous large red-orange granules which will fill the cytoplasm and sometimes cover the nucleus.  0-8% in normal blood, increased in parasitic infections, asthma, hay fever, and many other diseases.
Hypersegmented neutrophil	Oil immersion view shows a hypersegmented neutrophil, which has at least six nuclear lobes (the normal neutrophil generally has 2-5 lobes), consistently seen in megaloblastic anemias.  Oval macrocytes and distorted RBC's (poikilocytosis) may also be seen.
Normal small lymphocyte	Normal small lymphocyte with its pale blue cytoplasm and dense, dark-staining nucleus. Note: the size of the nucleus is approximately the same size of normal red blood cells (approximately 7 microns).  16-46% in a normal adult blood smear, increased in infectious mononucleosis, lymphocytic leukemia, and many other diseases
Basophilia	Amount of RNA in each cell: Represented by bluish hue in cytoplasm of RBC. Basophilia normally decreases with cell maturity
Supravital stain	Stain that colors cells while they're still alive; i.e., adding stain to blood, allowing time to stain, and then making smear. For example, new methylene blue as used for reticulocyte staining.
Anisocytosis	Varying sizes (diameter) of RBC on peripheral smear
Poikilocytosis	Varying shapes of RBC on peripheral smear
Anisochromia	Two cell populations circulating simultaneously. One population is microcytic and hypochromic, and the other is normocytic and normochromic. This occurs in three places only: (1) treated iron deficiency anemia; (2) post transfusion of a hypochromic patient with a normochromic donor; (3) sideroblastic anemia.
Hypochromia	Normal erythrocytes tend to have a central pale area that is less than 1/3 of the cell diameter. Hypochromia is present when the pale area is larger than this
Methemoglobinemia	Erythrocytes (RBCs) possess 4 hemoglobin chains, each of which contains a heme moiety. These hemoglobin chains function to transport and deliver oxygen to tissues. Methemoglobin can be found in RBCs when there is oxidation (ie, loss of an electron) of the iron moiety, changing the normal oxygen-carrying ferrous (Fe2+) state to the ferric (Fe3+) state. Ferric heme is incapable of binding oxygen because of a stoichiometric alteration of the molecule	Oxidation of iron to the ferric state reduces the oxygen-carrying capacity of hemoglobin and produces a functional anemia. In addition, a ferric heme group affects nearby ferrous heme groups. Ferric heme groups impair the release of oxygen from nearby ferrous heme groups on the same hemoglobin tetramer. The result of methemoglobinemia is that oxygen delivery to tissues is impaired and the oxygen hemoglobin dissociation curve shifts to the left. Organs with high oxygen demands (ie, CNS, cardiovascular system) usually are the first systems to manifest toxicity. Oxygenated blood is red, deoxygenated blood is blue, and blood-containing methemoglobin is a dark reddish brown color. This dark hue imparts clinical cyanosis when methemoglobin levels are at 1.5 g/dL (approximately 10-15% methemoglobin concentration); however, a level of 5 g/dL of deoxygenated blood is required for similar effects. Therefore, when methemoglobin levels are relatively low, cyanosis may be observed without cardiopulmonary symptoms.
Dohle Body	The arrow points to a Dohle body in a neutrophil. Dohle bodies are basophilic cytoplasm left over from the progranulocyte stage of development. They represent rapid turnover of cells and are seen together with toxic granulation.
Alder-Reilly Anomaly	This was observed in a child with gargoylism. The anomaly is characterized by prominent granules (similar to toxic granulation) in the cytoplasm of segmented neutrophils, lymphocytes and monocytes. The anomaly is found in mucopolysaccharide disorders.
Pelger-Huet anomaly	Congenital autosomal dominant disorder in which granulocyte nuclei fail to segment normally. In the homozygote state the nucleus is round. In heterozygotes most granulocytes have bilobed nuclei ("pince-nez" cells) resembling bands. The trait is benign and occurs in 1 in 6,000 people. Cell function is normal.
May-Hegglin anomaly	Rare autosomal dominant abnormality characterized by large pale basophilic inclusions resembling Dohle bodies and appear to be altered RNA. Giant platelets, and sometimes thrombocytopenia are associated with this. The anomaly is usually benign but may be associated with bleeding.
Nucleolus	a small round body of protein in a cell nucleus; such organelles contain RNA and are involved in protein synthesis. Become enlarged during protein synthesis and contain the DNA template for ribosomal RNA.
L1 Subtype Leukemia	FAB L1 (85%) The blasts of the L1 subtype are small, often no larger than normal small peripheral blood lymphocytes. The nuclei are usually round, but may be slightly oval and indented. Nucleoli frequently are not visible. The cytoplasm is scant and grey to light blue in color. Cytoplasmic granules are usually absent, but may be seen in some cases, especially in those that are Philadelphia chromosome positive. The cell surface may be smooth or show fine membrane projections.
L2 Subtype Leukemia	In the L2 subtype of ALL the cell size is more variable, but is usually larger by 1 1/2 to 2 times than that of the L1 subtype. The cytoplasm is more abundant and grey to blue in color. Cytoplasmic vacuoles and granules usually are not present. The nuclear contour is more variable with more indentations, and the nuclear chromatin is more clumped and one or more prominent nucleoli are usually visible. Nuclei may be cleft. From a morphologic standpoint alone L2 ALL, and M0 and M1 AMLs cannot be distinguished unless Auer rods are seen (M1).
L3 Subtype Leukemia	The morphologic appearance of the malignant cells in L3 ALL/lymphoma (Burkitt's leukemia/lymphoma) on a Wright-Giemsa stain is essentially diagnostic, especially in the classic subtype. The cells are of medium size, about 1 1/2 to 2 times larger than L1 ALL cells, and they are rather uniform in size. The cytoplasm is very basophilic (blue) and contains a variable number of lipid-laden vacuoles that stain positive with oil red 0 (neutral fat). The vacuoles frequently cluster in a Golgi distribution. The nucleus is round to slightly oval, and the nuclear chromatin is coarse but evenly dispersed with some clumping. Nucleoli are prominant and usually multiple in number. On fixed paraffin sections of bone marrow and lymph node specimens the pattern of infiltration is diffuse with a "starry sky" appearance due to histiocytic engulfment of apoptotic Burkitt tumor cells. Mitotic figures are frequent reflecting the very high proliferative rate. Resting cells are essentially non-existent
HAM test	HAM Test/ Acid Serum Test/ PNH Test/ Paroxysmal Noctural Hemoglobinuria test, Serum lysis	HAM test is used to evaluate patients with suspected PNH (Paroxysmal Noctural Hemoglobinuria) or suspected congential dyserythropoietic anemia, especially with hemosiderinuria, Pancytopenia, decreased RBC acetyl cholinesterase, decreased leukocyte alkaline phosphatase, negative direct Coomb’s test, and/or apparent marrow failure. Diagnosis of PNH shows that the suspected patient’s red cells have a high sensitivity to complement mediated hemolysis. Partial hemolysis occurs with hereditary erythroblastic multinuclearity disease. PNH is a disease of increased complement sensitivity of red ell membranes, granulocytes and platelet membrane. Positive test result shows lysis of Red cells in acidified serum samples with patients cell (not with normal cells). Flow cytometry is now the preferred method for PNH screening where a population of CD55 and / or CD59 cells is diagnostic of PNH Hams test is still indicated in the investigation of HEMPAS. Contact the laboratory. HEMPAS (Hereditary ertyhroblastic multinuclearity with an acidified serum lysis test) or Congenital Dyserythropoietic Anemia type 2 (CDAN2): This syndrome is so clearly different from PNH that no difficulty in distinguishing them is apparent. It is a congenital disorder and is characterized by ineffective erythropoiesis with marked multinuclearity of the erythroblast. The red blood cells, once circulating, have a relatively normal survival. This AR condition is characterized by an IgM autoantibody against the RBC's i antigen–'anti-HEMPAS', an antigen is present in1⁄3 of normal sera but absent in the HEMPAS patients. The reactions that bring about the lysis of the red blood cells in acidified normal serum are very different from those that cause lysis of PNH cells. In this case, the lysis is mediated by an IgM antibody that is present in most normal serum that reacts with an antigen present only on the cells of HEMPAS patients with this syndrome; this antibody can be absorbed from normal serum by HEMPAS cells but not by normal cells. The serum of patients with the disorder always lack the antibody and thus, unlike the case in PNH lysis does not occur in autologous serum.
Evans Syndrome	Basically it is ITP and AIHA that is Coombs DAT positive	Evans syndrome is an uncommon condition defined by the combination (either simultaneously or sequentially) of immune thrombocytopenia (ITP) and autoimmune haemolytic anaemia (AIHA) with a positive direct antiglobulin test (DAT) in the absence of known underlying etiology. This condition generally runs a chronic course and is characterized by frequent exacerbations and remissions. First-line therapy is usually corticosteroids and/or intravenous immunoglobulin, to which most patients respond; however, relapse is frequent. Options for second-line therapy include immunosuppressive drugs, especially cyclosporine or mycophenolate mofetil; vincristine; danazol or a combination of these agents. More recently a small number of patients have been treated with rituximab, which induces remission in the majority although such responses are often sustained for <12 months and the long-term effects in children are unclear. Splenectomy may also be considered although long-term remissions are less frequent than in uncomplicated ITP. For very severe and refractory cases stem cell transplantation (SCT) offers the only chance of long-term cure. The limited data available suggest that allogeneic SCT may be superior to autologous SCT but both carry risks of severe morbidity and of transplant-related mortality. Cure following reduced-intensity conditioning has now been reported and should be considered for younger patients in the context of controlled clinical trials.
Reed Sternberg Cells	Malignant cells B-cell
Lacunar Cells or Popcorn	Hodgkin lymphoma, nodular lymphocyte predominant type. L&H (popcorn) cells are large cells with folded nuclei resembling a popped kernel of corn (arrow), usually CD20 positive and surrounded by small T lymphocytes that express CD57.
Purine	Purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. Purines, including substituted purines and their tautomers, are the most widely distributed kind of nitrogen-containing heterocycle in nature. Purines and pyrimidines make up the two groups of nitrogenous bases, including the two groups of nucleotide bases. Two of the four deoxyribonucleotides and two of the four ribonucleotides, the respective building blocks of DNA and RNA, are purines.
Pyrimidine	Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring.[1] It is isomeric with two other forms of diazine. Three nucleobases found in nucleic acids (cytosine, thymine, and uracil) are pyrimidine derivatives: In DNA and RNA, these bases form hydrogen bonds with their complementary purines. Thus the purines adenine (A) and guanine (G) pair up with the pyrimidines thymine (T) and cytosine (C), respectively. In RNA, the complement of A is U instead of T and the pairs that form are adenine:uracil and guanine:cytosine.
Watson-Crick Pairing
Thymidine Mono phosphate
Major groove Minor groove	Nucleic acids also exist in at least three helical isomeric forms: A, B and Z. B form is typical of dsDNA: 10 bp per turn, 0.33 nm 'rise' in 'height' per base pair. A form is typical of dsRNA and DNA/RNA hybrids: 11 bp per turn. Z form is probably very rare. It is left handed, only has one groove, and is only stable under conditions of high ionic strength and/or in very GC rich DNA.

Peripheral blood (red cell) abnormalities and their associated diseases.
Abnormality	Description	Associated diseases
Acanthocytosis	Small cells with thorny projections.	Abetalipoproteinemia.
Anisocytosis	Abnormal variation in size.	Any severe anemia.
Heinz Bodies	Small, round inclusions of denatured hemoglobin seen under phase microscopy or with supravital staining.	Congenital hemolytic anemias resulting in hemoglobin precipitates (e.g. glucose-6-phosphate dehydrogenase deficiency).
Nucleated Red Cell	Erythrocyte with a nucleus still present.	Marked marrow erythroid hyperplasia or marrow replacement (i.e. tumor cells).
Pappenheimer bodies	Siderotic granules, staining blue with Wright or Prussian blue stain.	Increased marrow iron, absent spleen, and some hemolytic anemias.
Poikilocytosis	Abnormal variation in shape.	Any severe anemia.
Rouleaux	Aggregated erythrocytes regularly stacked on one another.	Multiple myeloma, cold agglutinin disease, viral infections.
Schistocytes	Irregularly shaped cells or cell fragments (severe poikilocytosis).	Disseminated intravascular coagulation, microangiopathic hemolytic anemia, thrombotic thrombocytopenic purpura, and uremia.
Sickle Cells	Crescent-shaped cells.	Sickle cell hemoglobinopathies.
Spherocytosis	Spherical cells without pale centers; often small.	Hereditary spherocytosis, Coombs-positive hemolytic anemias.
Stomatocytosis	Red cells with slit-like, instead of circular, areas of central pallor.	Congenital hemolytic anemia, thalassemia, burns, lupus erythematosus, lead poisoning, and liver disease.
Target Cells	Cells with a dark center and periphery and clear ring in-between.	Thalassemia, liver disease, Hemoglobinopathies (S, C, SC, S-thalassemia).