Immunohematology Seminar 2 Review

0.0(0)
studied byStudied by 0 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/80

flashcard set

Earn XP

Description and Tags

81 vocabulary flashcards covering key terms, antigens, antibodies, phenotypes, tests and discrepancies discussed in the Immunohematology seminar.

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

81 Terms

1
New cards

Immunohematology

Serologic, genetic, biochemical and molecular study of blood-cell antigens and their immune reactions.

2
New cards

Transfusion Medicine

Multidisciplinary specialty covering blood donation, component preparation, serology and clinical transfusion therapy.

3
New cards

Blood Banking

Branch of transfusion medicine focused on testing, storing and issuing compatible blood to optimize patient outcomes.

4
New cards

ABO Blood Group

Most immunogenic carbohydrate blood-group system; antibodies form naturally and are critical in transfusion compatibility.

5
New cards

Rh Blood Group

Protein antigen system discovered by Landsteiner & Wiener; D antigen is highly immunogenic and routinely typed.

6
New cards

Karl Landsteiner

Discovered the ABO blood group system in 1901, explaining causes of incompatible transfusions.

7
New cards

William Harvey

Rediscovered systemic blood circulation in 1628, laying groundwork for transfusion science.

8
New cards

Hemolytic Disease of the Fetus and Newborn (HDFN)

Maternal IgG antibodies cross placenta and destroy fetal red cells, causing anemia and hyperbilirubinemia.

9
New cards

Antiglobulin Test (Coombs’ Test)

Assay using anti-human globulin to detect IgG or complement bound to red cells.

10
New cards

Direct Antiglobulin Test (DAT)

One-step AHG test that detects in vivo-coated red cells with IgG and/or complement.

11
New cards

Indirect Antiglobulin Test (IAT)

Two-step AHG test that detects in vitro-sensitized red cells in antibody screening, identification and crossmatch.

12
New cards

Alloantibody

Antibody produced against antigens not present on the producer’s own cells.

13
New cards

Autoantibody

Antibody that reacts with antigens on the individual’s own red cells.

14
New cards

IgM

Pentameric, naturally occurring, cold-reactive antibody class; best complement activator.

15
New cards

IgG

Monomeric antibody reacting at 37 °C, crosses placenta, causes extravascular hemolysis.

16
New cards

Forward Grouping

ABO typing that detects antigens on patient RBCs using known antisera.

17
New cards

Reverse Grouping

ABO typing that detects serum antibodies with reagent A1 and B red cells.

18
New cards

Rouleaux Formation

Stacking of red cells due to increased plasma proteins, mimicking agglutination.

19
New cards

Lectin

Plant protein that specifically agglutinates certain blood groups (e.g., Dolichos biflorus for A1).

20
New cards

Gel Technology

Method where agglutinated red cells are trapped in dextran-acrylamide gel microtubes after centrifugation.

21
New cards

H Antigen

Precursor molecule on which A and B antigens are built by specific transferases.

22
New cards

FUT1 Gene

Chromosome 19 gene encoding α-1,2-L-fucosyltransferase that forms H antigen on red cells.

23
New cards

Secretor (Se) Gene

FUT2 allele that allows expression of ABH substances in body secretions.

24
New cards

Bombay Phenotype (Oh)

hh genotype lacking H antigen; serum contains anti-A, anti-B, anti-AB and potent anti-H.

25
New cards

Para-Bombay Phenotype

Rare phenotype with minimal or absent H antigen on RBCs but ABH substances may be secreted, depending on FUT1/FUT2 status.

26
New cards

A1 Subgroup

Common A phenotype reacting with anti-A and anti-A1; ~1 million antigen sites per cell.

27
New cards

A2 Subgroup

A phenotype reacting with anti-A but not anti-A1; fewer antigen sites and more detectable H antigen.

28
New cards

Weak A Subgroup

Phenotypes with greatly reduced A antigen expression, variable agglutination and strong anti-H reaction.

29
New cards

Anti-A1

Naturally occurring IgM found in some A2/A2B persons; reacts with A1 cells and seldom causes transfusion issues.

30
New cards

Anti-H

IgM antibody targeting H antigen; strong in Bombay sera, weak in some A1 individuals.

31
New cards

ABO Discrepancy Group I

Reverse-grouping problem due to weak or missing serum antibodies.

32
New cards

ABO Discrepancy Group II

Forward-grouping problem caused by weak or missing red-cell antigens.

33
New cards

ABO Discrepancy Group III

Forward and reverse issues produced by plasma abnormalities, leading to rouleaux/pseudo-agglutination.

34
New cards

ABO Discrepancy Group IV

Miscellaneous typing problems such as cold autoantibodies, polyagglutination or cis-AB.

35
New cards

Fisher-Race Nomenclature

Rh terminology using D, C/c and E/e to denote three closely linked genes.

36
New cards

Weiner Nomenclature

Rh terminology representing complex agglutinogens (e.g., R0, R1, r) encoded by a single locus.

37
New cards

Weak D

Reduced D antigen density requiring IAT for detection; individuals type Rh-positive for transfusion.

38
New cards

Partial D (Mosaic D)

Phenotype missing portions of the D antigen; affected individuals may form anti-D.

39
New cards

Del Phenotype

Extremely low D antigen expression detectable only by adsorption–elution methods.

40
New cards

Rh Null

Absence of all Rh antigens, usually due to RhAG defects; associated with stomatocytosis and hemolytic anemia.

41
New cards

Rh-Associated Glycoprotein (RhAG)

Membrane co-expressor required for surface display of Rh proteins; absence causes Rh null phenotype.

42
New cards

f Antigen (ce)

Compound antigen expressed when c and e are inherited on the same chromosome.

43
New cards

G Antigen

Epitope present on most D-positive or C-positive RBCs; anti-G mimics anti-D + anti-C.

44
New cards

Coombs’ Control Cells

IgG-sensitized red cells added to negative AHG tests to confirm reagent activity.

45
New cards

Hemolytic Transfusion Reaction (HTR)

Immune destruction of transfused RBCs by recipient antibodies; may be acute or delayed.

46
New cards

Kleihauer-Betke Test

Acid-elution smear quantifying fetal RBCs in maternal blood to calculate RhIg dose.

47
New cards

RhoGAM

Concentrated anti-D immune globulin given to Rh-negative mothers to prevent Rh immunization.

48
New cards

Lewis Blood Group

Fucosylated antigens produced in tissues and adsorbed onto RBCs; phenotypes depend on Le and Se genes.

49
New cards

Anti-Lea

Naturally occurring IgM that can fix complement and occasionally hemolyze transfused RBCs.

50
New cards

MNS Blood Group

Glycophorin-based antigens (M, N, S, s, U) showing dosage and sensitivity to proteolytic enzymes.

51
New cards

Anti-M

Usually IgM, pH-dependent antibody that often shows dosage and rarely causes HDN.

52
New cards

P Blood Group

System containing P, P1 and Pk antigens; antibodies include anti-P1 and Donath–Landsteiner anti-P.

53
New cards

Donath–Landsteiner Antibody

Biphasic IgG anti-P that causes paroxysmal cold hemoglobinuria.

54
New cards

I Blood Group

Developmental system in which newborns are i-positive and adults I-positive.

55
New cards

Autoanti-I

Cold autoantibody often associated with Mycoplasma pneumoniae infection and cold agglutinin disease.

56
New cards

Kell Blood Group

Highly immunogenic protein system; K antigen ranks second to D in clinical importance.

57
New cards

McLeod Phenotype

X-linked absence of Kx antigen with weakened Kell expression and acanthocytosis; linked to chronic granulomatous disease.

58
New cards

Duffy Blood Group

Fy antigens serve as receptors for Plasmodium vivax; Fy(a-b-) individuals resist infection.

59
New cards

Kidd Blood Group

Urea-transporter antigens Jka/Jkb; antibodies cause notorious delayed hemolytic transfusion reactions.

60
New cards

Jk(a-b-) Phenotype

Rare Kidd-null red cells resistant to 2 M urea lysis; may produce anti-Jk3.

61
New cards

Lutheran Blood Group

Poorly developed Lua and Lub antigens; anti-Lub may shorten survival of transfused cells.

62
New cards

Cold Reacting Antibody

Usually IgM; agglutinates best at or below room temperature (22–25 °C).

63
New cards

Warm Reacting Antibody

Usually IgG; reacts optimally at body temperature (37 °C).

64
New cards

PEG (Polyethylene Glycol)

Enhancement medium that concentrates antibodies by removing water during IAT.

65
New cards

DTT (Dithiothreitol)

Sulfhydryl reagent used to break IgM pentamers or treat RBCs to eliminate IgM-mediated agglutination.

66
New cards

Chimerism

Presence of two genetically distinct red-cell populations in one individual.

67
New cards

Polyagglutination

Exposure of crypt antigens on RBCs causing universal agglutination with most adult sera.

68
New cards

Acquired B Phenomenon

Bacterial de-acetylation of A antigen, transiently making group A cells react with anti-B sera.

69
New cards

Hydatid Cyst Fluid

Source of soluble P1 substance used to neutralize anti-P1 antibodies.

70
New cards

Stomatocyte

Cup-shaped red cell commonly seen in Rh null phenotype.

71
New cards

Kleihauer Betke Percentage

% Fetal cells = (fetal cells ÷ total RBCs) × 100; used to estimate fetomaternal hemorrhage.

72
New cards

MicRhoGAM

50 µg dose of anti-D immunoglobulin for Rh-negative women with first-trimester pregnancy events.

73
New cards

Paroxysmal Cold Hemoglobinuria (PCH)

Hemolytic anemia triggered by cold; mediated by Donath–Landsteiner antibodies against P antigen.

74
New cards

Co-dominant

Genetic expression in which both alleles are fully manifested, e.g., Lutheran Lua and Lub.

75
New cards

Dosage Effect

Stronger antibody reactions with homozygous antigen expression than with heterozygous cells.

76
New cards

Enzyme-treated Cells

RBCs exposed to proteases; enhance some antigens (Rh, Kidd) and destroy others (Duffy, MNS).

77
New cards

ISBT Number

Six-digit standardized code assigned to each blood-group antigen (e.g., 004001 = D).

78
New cards

Agglutinogen

Complex of antigens encoded by a single locus in Weiner Rh nomenclature.

79
New cards

Glycosyltransferase

Enzyme that adds specific sugar residues to precursor chains, forming blood group antigens.

80
New cards

Complement Fixation

Activation of complement cascade by antigen-antibody complexes, potentially leading to hemolysis.

81
New cards

Alloimmunization

Immune response to foreign blood-group antigens after transfusion or pregnancy, producing alloantibodies.