Hematology Lecture Notes - Hemoglobin, Anemia, WBCs & Leukemias

Comprehensive vocabulary flashcards generated from the Week 10 Hematology lecture on Hemoglobin, Hemoglobinometry, Electrophoresis, Derivatives, Anemias, White Blood Cells, Granulopoiesis, WBC Anomalies, and Leukemias.

Hemoglobinometry

The laboratory measurement of the concentration or level of hemoglobin present in a blood specimen.

Cyanmethemoglobin (HiCN) Method

The reference method for hemoglobin determination in which hemoglobin is oxidized to methemoglobin by potassium ferricyanide and subsequently coupled with potassium cyanide to form cyanmethemoglobin, read photometrically at $540\,nm$.

Drabkin's Reagent

A reagent used in the cyanmethemoglobin method whose major components are potassium ferricyanide ($K_3Fe(CN)_6$), which converts hemoglobin to methemoglobin, and potassium cyanide ($KCN$), which provides cyanide ions.

Beer-Lambert's Law

A physical law stating that the absorbance of monochromatic light passing through a solution is directly proportional to both the concentration of the absorbing substance and the path length of the sample.

Sodium Lauryl Sulfate (SLS) Method

A hemoglobin measurement method utilized by Sysmex automated analyzers that transforms hemoglobin into SLS-methemoglobin without generating toxic cyanide waste.

HemoCue

A handheld system commonly used in blood bank donor selection that converts hemoglobin to azidemethemoglobin and measures concentration photometrically at two wavelengths ($570\,nm$ and $880\,nm$).

Cellulose Acetate Electrophoresis

A primary screening procedure for variant hemoglobins performed at an alkaline pH ($8.4 - 8.6$), where negatively charged hemoglobin molecules migrate toward the positive pole (anode).

Citrate Agar Electrophoresis

A confirmatory hemoglobin electrophoresis procedure conducted at an acid pH ($6.0 - 6.2$) used to definitively separate $Hb\,S$ from $Hb\,D$ and $Hb\,G$, and $Hb\,C$ from $Hb\,E$, $Hb\,O_{Arab}$, and $Hb\,C_{Harlem}$.

Hemoglobin A1

The major adult form of hemoglobin ($\alpha_2\beta_2$), comprising $97\%$ of circulating adult hemoglobin, which exhibits the fastest anodic migration speed among normal hemoglobins on cellulose acetate at pH $8.4 - 8.6$.

Ferrochelatase

Also known as heme synthetase, the mitochondrial enzyme required to insert ferrous iron ($Fe^{2+}$) into the protoporphyrin IX ring to form heme.

Embryonic Hemoglobins

Early developmental hemoglobin species—specifically Portland ($\zeta_2\gamma_2$), Gower 1 ($\zeta_2\epsilon_2$), and Gower 2 ($\alpha_2\epsilon_2$)—that are present during embryonic life but completely absent in newborn and adult blood.

Hemoglobin F (Hb F)

Fetal hemoglobin ($\alpha_2\gamma_2$), which is the predominant hemoglobin in fetuses and newborns ($80\%$) and persists at less than $1\%$ in normal adult blood.

Oxyhemoglobin

A functional hemoglobin derivative ($HbO_2$) containing ferrous iron ($Fe^{2+}$) bound to oxygen, assuming a relaxed (R) state conformation and imparting a bright red color to arterial blood.

Deoxygenated Hemoglobin

A functional hemoglobin derivative containing ferrous iron ($Fe^{2+}$) not bound to oxygen, assuming a tense (T) state conformation and imparting a dark red color to venous blood.

Carboxyhemoglobin

A dyshemoglobin ($HbCO$) formed when carbon monoxide binds to ferrous iron ($Fe^{2+}$) with a 240-fold higher affinity than oxygen, turning blood and skin cherry red.

Methemoglobin

A dyshemoglobin ($Hi$) containing oxidized ferric iron ($Fe^{3+}$) that cannot bind oxygen, turning blood chocolate brown.

Sulfhemoglobin

An unquantifiable mixture of oxidized, partially denatured hemoglobin forms ($SHb$) that cannot be converted to cyanmethemoglobin and imparts a mauve-lavender color to blood.

Anemia

A clinical manifestation of an underlying disease defined by a decrease below normal in red blood cell count, hemoglobin concentration, or hematocrit.

Aplastic Anemia

A rare, life-threatening bone marrow failure syndrome characterized by pancytopenia, reticulocytopenia, bone marrow hypocellularity, and depletion of hematopoietic stem cells.

Fanconi Anemia

The most common inherited aplastic anemia, characterized by DNA chromosome instability, cancer susceptibility, and physical anomalies such as thumb malformations, microcephaly, and café-au-lait lesions.

Paroxysmal Nocturnal Hemoglobinuria (PNH)

An acquired stem cell disorder resulting from a defect in GPI-anchored proteins that causes a deficiency in complement regulatory proteins DAF and MIRL, leading to complement-mediated intravascular hemolysis.

Anemia of Chronic Inflammation (ACI)

An anemia characterized by sideropenia (decreased serum iron) despite abundant tissue iron stores, driven by inflammatory cytokines and elevated hepcidin.

Hepcidin

The master regulatory hormone and acute phase reactant for systemic iron metabolism that functions by inactivating ferroportin, preventing iron release from storage tissue into the plasma.

Ferroportin

A transmembrane protein that transports stored iron from macrophages and tissue cells into the blood circulation.

Koilonychia

An abnormal concave, spoon-shaped curvature of the fingernails seen as a clinical feature in severe iron deficiency anemia.

Pagophagia

A specific type of pica characterized by the compulsive craving and eating of ice, commonly seen in iron deficiency anemia.

Total Iron-Binding Capacity (TIBC)

A laboratory test that indirectly measures serum transferrin concentration by determining its maximal capacity to bind iron.

Pernicious Anemia

A megaloblastic anemia caused by autoimmune destruction of parietal cells or intrinsic factor, preventing terminal ileal absorption of vitamin B12.

Holotranscobalamin (holoTC)

The metabolically active circulating complex consisting of vitamin B12 bound to transcobalamin.

Type II Myeloblast

An immature granulocytic precursor with fine chromatin and visible nucleoli that contains up to 20 primary (azurophilic) granules per cell.

Promyelocyte

The largest cell in the granulocytic series ($16 - 25\,\mu m$) containing abundant primary azurophilic granules and a prominent cytoplasmic clear area known as a "hof".

Dawn of Neutrophilia

The microscopic appearance of pale pink secondary (specific) granules near the Golgi complex in an early myelocyte.

Metamyelocyte

Also known as a juvenile cell, a non-mitotic granulocytic precursor ($14 - 16\,\mu m$) exhibiting the first stage of nuclear indentation (kidney bean or peanut shape) extending less than half the nuclear width.

Band Cell

The youngest granulocytic precursor normally found in peripheral blood, featuring a sausage-shaped nucleus with an indentation exceeding half the nuclear width.

Pseudoneutrophilia

A temporary, physiological elevation of circulating neutrophils caused by a shift from the marginated pool to the circulating pool due to stress, exercise, or temperature changes without true bone marrow overproduction.

Agranulocytosis

An extreme, severe form of neutropenia characterized by a peripheral blood neutrophil count of less than $0.5 \times 10^9\,L^{-1}$.

Plasma Cell

A fully differentiated B lymphocyte with an eccentric cartwheel/clock-face nucleus and dark blue cytoplasm that synthesizes immunoglobulins, which can accumulate as Russell bodies.

Macrophage

The most abundant tissue cell type in the body ($40 - 50\,\mu m$), derived from circulating blood monocytes, responsible for phagocytosis, nitric oxide synthesis, IL-1 release, and transcobalamin production.

Kupffer Cells

The specialized, resident tissue macrophages residing in the liver.

Osteoclasts

Large multinucleated macrophage-lineage cells responsible for bone resorption.

Levy Chamber with Improved Neubauer Ruling

The standard counting chamber used in manual hemocytometry, consisting of 9 large square millimeters where the 4 corner squares are subdivided into 16 small squares for white blood cell counting.

Corrected WBC Count

A mandatory mathematical correction performed when $\,\ge 5$ nucleated RBCs per 100 WBCs are seen on a blood smear, calculated as $\text{Uncorrected WBC} \times \frac{100}{100 + \%NRBC}$.

Absolute WBC Count

The concentration of a specific leukocyte subtype per microliter of blood, calculated as $\text{Relative Count} \times \text{Total WBC Count}$.

Degenerative Shift to the Left

An increase in immature neutrophil forms in peripheral blood accompanied by a normal or low total WBC count, characteristic of overwhelming infections such as tuberculosis.

Regenerative Shift to the Left

An increase in immature neutrophil forms in peripheral blood accompanied by an elevated total WBC count, characteristic of conditions like appendicitis.

Leukoerythroblastic Reaction

A marrow stress response characterized by the simultaneous peripheral blood presence of immature neutrophils, nucleated RBCs, and teardrop RBCs (dacrocytes).

Pick's Cell (Foam Cell)

A tissue macrophage filled with small lipid droplets giving its cytoplasm a bubbly or foamy appearance, characteristic of Niemann-Pick disease.

Gaucher Cell

A large bone marrow macrophage with a small eccentric nucleus and cytoplasm distended by accumulated glucocerebrosides, exhibiting a crumpled tissue paper or onion skin appearance.

Chediak-Higashi Syndrome

A rare autosomal recessive immune dysregulation disorder caused by a Golgi complex defect, resulting in giant dysfunctional lysosomal granules in leukocytes and partial albinism.

May-Hegglin Anomaly

An autosomal dominant disorder characterized by giant platelets, variable thrombocytopenia, and spindle-shaped, blue Dohle body-like inclusions in leukocytes.

Pelger-Huët Anomaly

An autosomal dominant disorder caused by lamin $\beta$-receptor mutation, resulting in hyposegmented neutrophils with bi-lobed spectacle-like ("pince-nez") or uni-lobed nuclei.

Lupus Erythematosus (LE) Cell

An in vitro neutrophil that has phagocytosed the antibody-coated denatured nucleus of another leukocyte, associated with Systemic Lupus Erythematosus.

Tart Cell

A monocyte that has ingested an intact lymphocyte or whole nuclear mass, commonly seen in drug sensitivity reactions.

Grape Cell (Mott Cell)

An abnormal plasma cell whose cytoplasm is completely filled with immunoglobulin-containing spherical Russell bodies, observed in plasma cell myeloma.

Reed-Sternberg Cell

A giant binucleated lymphoid cell with prominent eosinophilic nucleoli creating an owl's eyes appearance, serving as the pathognomonic histologic feature of Hodgkin's disease.

Auer Rods

Linear cytoplasmic projections composed of fused primary azurophilic granules found in leukemic myeloblasts and promyelocytes in acute myelogenous leukemia.

Faggot Cells

Leukemic promyelocytes containing dense bundles of Auer rods in their cytoplasm, pathognomonic for Acute Promyelocytic Leukemia (AML M3).

Dohle Bodies

Round or oval light-blue cytoplasmic inclusions composed of parallel rows of ribosomal RNA found in neutrophils during severe infections, burns, or pregnancy.

Myeloperoxidase (MPO) Stain

A cytochemical stain that detects peroxidase in primary granules of myeloid cells, yielding a positive reaction in AML (M1, M2, M3) to differentiate it from ALL.

Sudan Black B (SBB) Stain

The most sensitive cytochemical stain for granulocytic precursors that stains sterols, neutral fats, and phospholipids in primary and secondary granules.

Di Guglielmo's Syndrome

The classic synonym for Acute Erythroleukemia (AML M6), characterized by strongly PAS-positive erythroid precursors and macrocytic normochromic anemia.

Philadelphia Chromosome

An abnormally short chromosome 22 resulting from a reciprocal translocation $t(9;22)(q34.1;q11.2)$ that creates the $BCR\text{--}ABL1$ fusion gene, present in Chronic Myelogenous Leukemia.

Leukocyte Alkaline Phosphatase (LAP) Test

A cytochemical assay used to differentiate a Leukemoid Reaction (elevated LAP score) from Chronic Myelogenous Leukemia (decreased LAP score).