Blood Banking and Immunohematology Vocabulary

Comprehensive vocabulary flashcards covering basic genetics, ABO and Rh blood group systems, minor blood group systems, techniques, and adverse reactions based on lecture notes.

Law of Segregation

Mendel's First Law stating that each individual possesses two alleles for a trait which separate during gamete formation, resulting in each parent passing one allele to offspring.

Codominance

An inheritance pattern in which both alleles at a locus are expressed simultaneously without suppressing each other, as seen in most blood group systems.

Law of Independent Assortment

Mendel's Second Law stating that genes for different traits are inherited independently of one another unless they are closely linked on the same chromosome.

Hardy-Weinberg Principle

A mathematical principle used to calculate allele and genotype frequencies in a population using the formulas $p + q = 1$ and $p^2 + 2pq + q^2 = 1$.

Amorph

A silent allele that produces no detectable gene product, such as the O gene in the ABO system.

Antithetical Antigens

Two antigens produced by alternative alleles at the same locus, such as Jk\text{a}/Jk\text{b} or M/N.

Dosage Effect

A phenomenon where an antibody reacts more strongly with red blood cells that have homozygous antigen expression than with cells that have heterozygous expression.

H Gene (FUT1)

The gene located on chromosome 19 that produces \alpha-2-L-fucosyltransferase, adding L-fucose to type 2 precursor chains on red blood cells to form H antigen.

L-fucose

The immunodominant sugar responsible for H antigen specificity.

N-acetyl-D-galactosamine (GalNAc)

The immunodominant sugar added by \alpha-3-N-acetylgalactosaminyltransferase that confers A antigen specificity.

D-galactose

The immunodominant sugar added by \alpha-3-D-galactosyltransferase that confers B antigen specificity.

Bombay Phenotype (Oh)

A rare phenotype resulting from the hh genotype, lacking \alpha-2-L-fucosyltransferase and expressing no H, A, or B antigens while producing strong anti-A, anti-B, and anti-H.

Se Gene (FUT2)

The secretor gene that codes for \alpha-2-L-fucosyltransferase acting on type 1 precursor chains in secretory tissues to produce soluble ABH substances.

Dolichos biflorus

A plant lectin reagent that specifically agglutinates A1 or A1B red blood cells.

Ulex europaeus

A plant lectin reagent with H antigen specificity that reacts most strongly with blood group O and A2 red blood cells.

Acquired B Phenomenon

A transient condition primarily seen in group A1 patients with lower gastrointestinal disease, where bacterial deacetylase converts GalNAc into D-galactosamine, mimicking B antigen reactivity.

Rouleaux

The microscopic stacking of red blood cells like coins caused by elevated plasma proteins, producing false positive pseudoagglutination in blood bank testing.

RHAG Gene

A gene on chromosome 6 that codes for Rh-associated glycoprotein, acting as an essential coexpressor required for Rh protein expression on the red blood cell membrane.

Weak D

A variation in D antigen expression where red blood cells react weakly or non-reactively at immediate spin with anti-D reagent, requiring detection at the indirect antiglobulin phase.

Partial D (D Mosaic)

An altered D antigen structure lacking specific epitopes, allowing D-positive individuals to form an alloanti-D antibody if exposed to complete D antigens.

Rhnull Syndrome

A rare condition characterized by the complete absence of all Rh antigens on red blood cells, resulting in stomatocytosis and mild compensated hemolytic anemia.

Landsteiner-Wiener (LW) System

A distinct blood group system whose antigen expression depends on Rh proteins; anti-LW reacts strongly with D-positive cells, weakly with D-negative cells, and is negative with Rhnull cells.

Glycophorin A (GPA)

The major sialic-acid-rich transmembrane glycoprotein that carries the M and N antigens of the MNS blood group system.

Glycophorin B (GPB)

The transmembrane glycoprotein that carries the S, s, and U antigens of the MNS blood group system.

McLeod Phenotype

An X-linked phenotype caused by mutations at the XK locus, resulting in absent Kx and Km antigens, weakened Kell antigens, acanthocytosis, and association with Chronic Granulomatous Disease.

Direct Antiglobulin Test (DAT)

A laboratory procedure used to detect in vivo sensitization of red blood cells by IgG antibodies, complement components (C3d), or both.

Indirect Antiglobulin Test (IAT)

A laboratory procedure used to detect in vitro sensitization of red blood cells with IgG antibodies or complement.

Check Cells (Coombs Control Cells)

IgG-coated red blood cells added to all negative antiglobulin tests to confirm proper cell washing, functional AHG reagent, and correct reagent addition.

Elution

A procedure used to break antigen-antibody bonds and remove antibodies from the red blood cell surface into a liquid solution called an eluate.

Transfusion-Related Acute Lung Injury (TRALI)

A severe transfusion reaction occurring within 6 hours of transfusion, caused by donor antibodies against recipient HLA or neutrophil antigens, leading to noncardiogenic pulmonary edema.

Transfusion-Associated Graft-Versus-Host Disease (TA-GVHD)

A nearly fatal immune response where viable donor T lymphocytes attack recipient tissues, prevented by gamma irradiation of cellular blood products.

Kleihauer-Betke Test

An acid-elution quantitative assay used to measure the percentage of fetal red blood cells in maternal circulation to calculate the required dose of Rh Immune Globulin.