Hematology: Learn the Fact, See the Image Integrated Study

Comprehensive vocabulary flashcards covering the hematology lecture notes, including hematopoiesis, red blood cell indices, anemia classifications, leukocyte identification, acute and chronic leukemias, blood parasites, platelet function, and the coagulation cascade.

Hematopoiesis

Blood-cell production that occurs mainly in adult bone marrow.

Myeloid cells

A major group of blood cells that includes RBCs, platelets, granulocytes, and monocytes.

Lymphoid cells

Blood cells that include B cells, T cells, and NK cells.

Erythropoietin (EPO)

A hormone produced mostly by the kidneys; its production is stimulated by hypoxia to promote RBC production.

Mature RBC

A non-nucleated biconcave disc measuring about $7\text{--}8\,\mu\text{m}$ across with a lifespan of approximately $120\,\text{days}$.

Reticulocyte

An immature red blood cell containing residual RNA that finishes maturation in bone marrow or blood in about $1\text{--}2\,\text{days}$.

Hemoglobin (Hb) Molecule

A protein structure composed of $4$ globin chains and $4$ heme groups containing $\text{Fe}^{2+}$, capable of binding $4$ molecules of $\text{O}_2$.

HbA

The main adult hemoglobin, composed of $\alpha_2\beta_2$ globin chains.

HbA2

A small fraction of adult hemoglobin, composed of $\alpha_2\delta_2$ globin chains.

HbF

The main fetal hemoglobin, composed of $\alpha_2\gamma_2$ globin chains.

Globin Gene Locations

Alpha-globin genes are located on chromosome $16$, whereas beta-like globin genes reside on chromosome $11$.

Hematocrit (Hct / PCV)

The fraction of total blood volume occupied by RBCs, commonly reported as a percentage ($\%$).

Mean Corpuscular Volume (MCV)

An RBC index indicating the average red cell volume, calculated as \text{Hct (\%)} \times 10 / \text{RBC (million/\mu L)}, with a standard adult reference interval of $80\text{--}100\,\text{fL}$.

Mean Corpuscular Hemoglobin (MCH)

The average mass of hemoglobin per RBC, calculated as \text{Hb (g/dL)} \times 10 / \text{RBC (million/\mu L)}, typically ranging between $27\,\text{pg}$ and $33\,\text{pg}$.

Mean Corpuscular Hemoglobin Concentration (MCHC)

The concentration of hemoglobin relative to red cell volume, calculated as $\text{Hb} \times 100 / \text{Hct (\%)}$, typically ranging between $32\,\text{g/dL}$ and $36\,\text{g/dL}$.

Red Cell Distribution Width (RDW)

A parameter that quantifies the degree of variation in RBC size (anisocytosis), rather than mean size.

Adult Anemia Thresholds

Standard clinical thresholds defined as hemoglobin $\text{Hb} < 13\,\text{g/dL}$ in men and $\text{Hb} < 12\,\text{g/dL}$ in nonpregnant women.

Supravital Stains

Stains such as new methylene blue or brilliant cresyl blue used on unfixed, living cells to visualize reticulocyte RNA and Heinz bodies.

Reticulocyte Production Index (RPI)

An adjusted metric calculated as $\text{Corrected retic \%} / \text{supplied maturation factor}$, assessing if marrow output is appropriately compensating for anemia.

Coagulation Sodium Citrate Ratio

A $3.2\%$ sodium citrate tube with a mandatory $9:1$ blood-to-anticoagulant ratio; significant underfilling results in excess anticoagulant and artifactually prolonged clotting times.

Microcytosis and Hypochromia

RBC morphology characterized by small cell size ($\text{MCV} < 80\,\text{fL}$) and increased central pallor due to decreased hemoglobin content.

Iron Deficiency Anemia (IDA) Profile

A microcytic, hypochromic anemia pattern characterized by low serum ferritin, low serum iron, elevated total iron-binding capacity (TIBC), and elevated RDW.

Anemia of Inflammation Profile

An anemia driven by increased hepcidin that traps iron, resulting in low serum iron, low or normal TIBC, and normal or elevated ferritin.

Ring Sideroblast

A nucleated erythroid precursor in bone marrow demonstrating a ring of iron granules around the nucleus on Prussian blue staining due to defective heme synthesis.

Thalassemia

A hereditary disorder caused by reduced synthesis of globin chains, typically presenting with marked microcytosis and a relatively preserved or high RBC count.

Target Cell (Codocyte)

An RBC showing a central hemoglobin spot enclosed by a clear ring and an outer rim of hemoglobin; seen in thalassemias, hemoglobinopathies, and liver disease.

Alpha-Thalassemia Phenotypes

Conditions categorized by deleted genes: $1/4$ deleted is a silent carrier; $2/4$ is alpha trait; $3/4$ is HbH disease ($\beta_4$ tetramers); and $4/4$ is Hb Bart disease ($\gamma_4$ tetramers).

Mentzer Index

A screening ratio calculated as \text{MCV} / \text{RBC count (million/\mu L)}; values $< 13$ favor thalassemia trait, while values $> 13$ favor iron deficiency anemia.

Hemoglobin S (HbS)

An abnormal hemoglobin caused by a beta-chain point mutation substituting valine for glutamate at position $6$, leading to polymerization upon deoxygenation.

Sickle Cell (Drepanocyte)

An elongated, curved RBC with pointed ends resulting from the polymerization of deoxygenated HbS.

Sickle Solubility Screen

A qualitative screening test that detects the presence of HbS based on insolubility, but cannot distinguish sickle cell trait ($\text{HbAS}$) from sickle cell disease ($\text{HbSS}$).

Hemolysis Laboratory Markers

A clinical laboratory profile typically showing elevated reticulocytes, elevated LDH, elevated indirect (unconjugated) bilirubin, and decreased haptoglobin.

Heinz Body

An intra-erythrocytic inclusion of denatured, precipitated hemoglobin identifiable using supravital stains; splenic removal of these inclusions creates bite cells.

Bite Cell (Degmacyte) and Blister Cell

Abnormally shaped RBCs formed during splenic removal of precipitated hemoglobin (Heinz bodies) following oxidative injury.

G6PD Deficiency

An X-linked enzymatic defect reducing cellular protection against oxidative stress; triggers such as infections, fava beans, or oxidant drugs induce acute hemolysis.

Spherocyte

A small, spherical RBC with dense coloration and diminished or absent central pallor; classically seen in hereditary spherocytosis and immune-mediated hemolysis.

Schistocyte

A fragmented or helmet-shaped RBC resulting from mechanical injury or microangiopathic processes such as DIC, TTP, or HUS.

Teardrop Cell (Dacryocyte)

An RBC featuring one tapered, pointed end and one rounded end; classically associated with bone marrow fibrosis or marrow infiltration.

Echinocyte (Burr Cell)

An erythrocyte characterized by regularly spaced, blunt surface projections; frequently an artifact or associated with uremia and metabolic disorders.

Acanthocyte

An erythrocyte bearing irregularly spaced, variable-length pointed projections; associated with severe liver dysfunction or membrane lipid abnormalities.

Stomatocyte

A red blood cell exhibiting a linear, slit-like area of central pallor resembling a mouth; seen in inherited membrane defects, acquired conditions, or as an artifact.

Howell-Jolly Body

A discrete, round, dark-blue intra-erythrocytic nuclear remnant composed of DNA; typically observed following splenectomy or in hyposplenism.

Basophilic Stippling

Multiple small, diffuse blue granules throughout an RBC composed of aggregated ribosomal RNA; associated with lead poisoning, thalassemia, and sideroblastic states.

Pappenheimer Bodies

Iron-containing mitochondrial granules visible within RBCs on standard stains and confirmed as Prussian blue positive.

Cabot Ring

A threadlike, ring-shaped or figure-eight inclusion within erythrocytes linked to dyserythropoiesis.

Polychromasia

The presence of grayish-blue young erythrocytes on a Wright-stained blood film, reflecting residual ribosomal RNA and correlating with reticulocytosis.

Megaloblastic Anemia

A macrocytic anemia ($\text{MCV} > 100\,\text{fL}$) caused by defective DNA synthesis (most commonly vitamin B12 or folate deficiency), identified by macro-ovalocytes and hypersegmented neutrophils.

Hypersegmented Neutrophil

A neutrophil possessing $6$ or more nuclear lobes; a sensitive peripheral smear indicator of megaloblastic anemia or exposure to certain chemotherapy agents.

Methylmalonic Acid (MMA) Differentiation

A metabolite elevated in vitamin B12 deficiency alongside homocysteine, but remaining normal in folate deficiency.

Aplastic Anemia

A bone marrow failure syndrome characterized by peripheral pancytopenia, an inappropriately low reticulocyte count, and a markedly hypocellular bone marrow.

Fanconi Anemia

An inherited condition characterized by chromosomal instability, progressive bone marrow failure, and cytopenias.

Neutrophil

A mature granulocyte with a segmented nucleus of $3\text{--}5$ lobes, pale cytoplasm, and fine secondary granules; functions as the primary defense against bacterial infections.

Eosinophil

A granulocyte characterized by a bilobed nucleus and large, refractive, orange-red cytoplasmic granules; associated with allergic reactions and helminthic infections.

Basophil

A granulocyte with prominent, coarse, dark purple-black granules containing histamine that frequently overlie and obscure the nucleus.

Small Lymphocyte

A mononuclear cell featuring a dense, round nucleus that occupies most of the cell volume, bordered by a thin rim of agranular cytoplasm.

Monocyte

The largest normal circulating leukocyte, featuring an indented, folded, or kidney-shaped nucleus and abundant grayish-blue cytoplasm.

Granulocytic Left Shift

An increase in circulating immature granulocytic forms (bands, metamyelocytes, myelocytes) in response to infection or inflammation.

Döhle Bodies and Toxic Granulation

Cytoplasmic findings in neutrophils associated with severe infection or inflammation; Döhle bodies represent aggregated rough endoplasmic reticulum, and toxic granulation represents prominent primary granules.

Pelger-Huët Anomaly

A benign inherited condition or acquired dysplastic state (pseudo-Pelger) characterized by neutrophils with hyposegmented, bilobed ('pince-nez') or unsegmented nuclei with mature chromatin.

Chédiak-Higashi Syndrome

A rare disorder presenting with giant lysosomal granules in white cells, partial albinism, thrombocytopenia, and severe recurrent bacterial infections.

Absolute Neutrophil Count (ANC)

The absolute circulating count of neutrophils, calculated as $\text{ANC} = \text{WBC} \times (\text{neutrophils \%} + \text{bands \%}) / 100$.

Blast Cell

A primitive, immature hematopoietic cell marked by a high nuclear-to-cytoplasmic (N:C) ratio, loose open chromatin, and visible nucleoli.

Auer Rod

A needle-like, azurophilic cytoplasmic inclusion formed by fused primary granules; definitive evidence of myeloid differentiation.

Acute Promyelocytic Leukemia (APL)

A distinct subtype of AML driven by the $t(15;17)$ translocation producing $PML::RARA$, characterized by abnormal promyelocytes with abundant Auer rods and high risk of life-threatening DIC.

Chronic Myeloid Leukemia (CML)

A myeloproliferative neoplasm characterized by granulocytic left shift, prominent basophilia, splenomegaly, and the Philadelphia chromosome translocation $t(9;22)$ generating $BCR::ABL1$.

Chronic Lymphocytic Leukemia (CLL)

A chronic leukemia characterized by sustained mature-appearing B lymphocytosis, smudge (basket) cells, and a clonal flow cytometry profile typically co-expressing CD5 and CD23.

Forward Scatter (FSC) vs Side Scatter (SSC)

Flow cytometry parameters where Forward Scatter measures approximate cell size and Side Scatter measures internal complexity or granularity.

Polycythemia Vera (PV)

A myeloproliferative neoplasm characterized by autonomous erythrocytosis, the $JAK2$ mutation, and characteristically suppressed erythropoietin (EPO) levels.

Reed-Sternberg Cell

A large, multinucleated giant cell ('owl-eye' appearance) pathognomonic for Hodgkin lymphoma, typically expressing CD15 and CD30.

Erythrocyte Sedimentation Rate (ESR)

A nonspecific indicator of systemic inflammation measured by the Westergren method; elevated by acute phase proteins that enhance rouleaux formation.

Plasmodium falciparum Ring Form

A delicate intracellular trophozoite form within non-enlarged RBCs, consisting of a fine ring of blue cytoplasm and a discrete chromatin dot; multiple rings may infect a single red cell.

Plasmodium falciparum Gametocyte

A distinctive crescent- or banana-shaped intra-erythrocytic sexual parasite form containing dispersed hemozoin pigment.

Plasmodium vivax Morphology

A malaria species characterized by enlarged infected RBCs, amoeboid trophozoites, and fine eosinophilic cytoplasmic stippling (Schüffner dots).

Thick vs Thin Blood Films

Thick blood films lyse erythrocytes to concentrate parasites for screening sensitivity; thin blood films preserve RBC architecture for species identification and parasitemia estimation.

Pseudothrombocytopenia

An in-vitro artifact caused by EDTA-induced platelet agglutination, yielding a falsely low automated platelet count; diagnosed by scanning the smear for platelet clumps.

Platelet Adhesion

The primary hemostatic stage where exposed subendothelial von Willebrand factor (vWF) binds directly to platelet membrane glycoprotein Ib (GPIb).

Platelet Aggregation

The primary hemostatic process where activated platelet surface glycoprotein IIb/IIIa (GPIIb/IIIa) receptors bind circulating fibrinogen molecules to bridge platelets.

Bernard-Soulier Syndrome

An inherited bleeding disorder caused by a quantitative or qualitative defect of glycoprotein Ib-IX-V (GPIb), characterized by impaired platelet adhesion, thrombocytopenia, and giant platelets.

Glanzmann Thrombasthenia

An inherited autosomal recessive bleeding disorder caused by a quantitative or qualitative deficiency of glycoprotein IIb/IIIa (GPIIb/IIIa), causing defective platelet aggregation.

Immune Thrombocytopenia (ITP)

An acquired autoimmune disorder mediated by anti-platelet autoantibodies causing isolated thrombocytopenia, with normal PT and aPTT values.

von Willebrand Disease (vWD)

An inherited bleeding disorder resulting from defective or deficient von Willebrand factor (vWF), impairing platelet adhesion and potentially decreasing circulating factor VIII levels.

Heparin-Induced Thrombocytopenia (HIT)

An immune-mediated prothrombotic complication triggered by heparin therapy, resulting in a precipitous platelet drop and paradoxically elevated risk of arterial or venous thrombosis.

Prothrombin Time (PT)

A screening coagulation assay that evaluates the extrinsic (Factor VII, Tissue Factor) and common (Factors X, V, II, I) coagulation pathways; monitored via the INR.

Activated Partial Thromboplastin Time (aPTT)

A coagulation assay that assesses the intrinsic pathway (Factors XII, XI, IX, VIII) and the common pathway (Factors X, V, II, I); used clinically to monitor unfractionated heparin therapy.

International Normalized Ratio (INR)

A standardized calculation expressed as $(\text{Patient PT} / \text{Mean Normal PT})^{\text{ISI}}$, used universally to assess oral warfarin therapy.

Thrombin Time (TT)

A screening coagulation test assessing the direct thrombin-mediated conversion of soluble fibrinogen to insoluble fibrin monomers; prolonged by dysfibrinogenemia, hypofibrinogenemia, or heparin.

Factor XIII (Fibrin-Stabilizing Factor)

A transglutaminase enzyme that cross-links insoluble fibrin polymers; its deficiency causes delayed bleeding complications despite completely normal PT and aPTT screening tests.

D-Dimer

A specific degradation product formed exclusively from plasmin-mediated breakdown of factor XIII cross-linked fibrin; serves as a sensitive marker of active coagulation and fibrinolysis.

Hemophilia A, B, and C

Hereditary factor deficiencies characterized by isolated aPTT prolongation and deep tissue/joint bleeding: Hemophilia A is Factor VIII deficiency, Hemophilia B is Factor IX deficiency, and Hemophilia C is Factor XI deficiency.

1:1 Mixing Study

An interpretive test mixing patient plasma $1:1$ with normal pooled plasma; correction indicates a factor deficiency, whereas non-correction indicates an inhibitor (e.g., lupus anticoagulant or factor antibody).

Lupus Anticoagulant (LA)

An antiphospholipid immunoglobulin that prolongs phospholipid-dependent clotting tests in vitro (e.g., dRVVT), but is paradoxically associated with venous and arterial thrombosis in vivo.

Disseminated Intravascular Coagulation (DIC)

A consumptive coagulopathy characterized by systemic microvascular thrombosis and secondary bleeding, presenting with thrombocytopenia, prolonged PT/aPTT, falling fibrinogen, and markedly elevated D-dimer.

Thrombotic Thrombocytopenic Purpura (TTP)

A thrombotic microangiopathy caused by severe deficiency of the ADAMTS13 metalloprotease, presenting with profound thrombocytopenia and abundant schistocytes, while PT and aPTT remain characteristically normal.

Protein C and Protein S

Vitamin K-dependent natural anticoagulant proteins; activated protein C (APC) complexes with cofactor protein S to cleave and inactivate factors Va and VIIIa.