Blood banking Flashcards
Study of transmission of inherited characteristics
Genetics
Genes expressed in equal frequency in males and females
Autosomal genes
Genes carried on X chromosomes
Sex-linked genes
A segment of DNA arranged along the chromosome at a specific locus
Gene
Genes in a locus that differs in their nucleotide sequence
Alleles
2 or more possible alleles at a locus
Polymorphic
2 or more different genes that may occupy a specific locus on a chromosome
Allelic
Opposite form of a gene
Antithetical
Genes occur in pairs; one gene is passed from parent to the offspring
Medelian Genetics
Genes occurs in pairs; one gene is passed from parent to the offspring
Mendelian Genetics
Two members of a single gene pair is passed from one generation to the next in separate genes
Law of Independent Segregation
Traits inherited from different chromosomes expressed separately and discretely
Law of Independent Assortment
The inheritance of a blood group antigens can be predicted using a ___
Punnett square
Inherits identical alleles at the same gene locus from both parents
Homozygous
Inherits different alleles at the same gene locus from each parent
Heterozygous
Concentration of antigens
Dosage effect
Genes inherited on the same chromosome
Cis
Genes are inherited on separate chromosomes
Trans
Genes that are close together on a chromosome and inherited as one unit
Linkage genes
Set of genes inherited via one of the two parental gametes
Haplotypes
Genes that do not produce a detectable trait
Amorphs
ABO ISBT
001
MNS ISBT
002
P ISBT
003
Rh ISBT
004
Lutheran ISBT
005
Kell ISBT
006
Lewis ISBT
007
Duffy ISBT
008
Kidd ISBT
009
Diego ISBT
010
Testing of genetic markers that are inherited to determine the presence or absence of a biological relationship
Relationship (Parentage) testing
RBC antigens
ABO
Rh
MNSs
Kell
Duffy
Kidd
Used when bands between the child and the alleged father do not match
Mismatch
Minimum of ___ mismatches is required before an opinion of nonpaternity
Two
Likelihood of paternity or probability of paternity
W value
W value must be ____ to suggest paternity
At least 95%
Occurs when a marker is detected in the child and is absent in the mother and the alleged father or when the alleged father’s phenotype demonstrates two markers and the child has neither of them
Direct or primary exclusion
Occurs when a single marker is detected in the child and a different single marker is detected in the alleged father
Indirect or secondary exclusion
Factors affecting agglutination
Temperature
Incubation time
pH
Ionic strength
Zeta potential
Zone of equivalence
Centrifugation
Optimum antigen-antibody ratio
40:1 = 2 drops of serum + 1 drop of 5% RCE
133:1 = 4 drops of serum + 1 drop of 3% RCS
An agglutination pattern in which numerous small clumps if cells exist amid a sea of free cells
Mixed field (mf)
Serologic testing of autoantibodies
Autocontrol
DAT
Serologic testing for alloantibodies
O cell control
Antibody screen
Crossmatch
DAT
2 diseases under alloimmune hemolytic anemia
HTR
HDFN
3 types of immune hemolytic anemia
Alloimmune HA
Autoimmune HA
Drug induced immune HA
Antibodies that can cause HTR and HDFN
IgG (warm reactive antibody)
Blood group with IgM antibody that can cause HTR, HDFN
ABO
Discovered the ABO blood group
Karl Landsteiner (1901)
Book (discovery of blood groups and their association with transfusion reaction
Specificity of Serologic Reactions (Karl Landsteiner) in 1917
Discovered blood type AB
Alfredo Descatello and Adriano Sturlie
3 genes that code for A, B, O are located on ___
Chrimosome 9q
ABO antigens are developed in utero at ___ of gestation; full expression occurs between ____
5-6 weeks;
2-4 years of age
Linkage of type 1
Beta-1,3
Linkage of type 2
Beta-1,4
Origin of type 1 oligosaccharide chains
Plasma
Origin of type 2 oligosaccharide
Seen on erythrocytic precursors
Controlling genes of type 1 oligosaccharide
H
A
B
Se
Lewis
Controlling genes of type 2 oligosaccharide
H
A
B
Composition of precursor substance RBC membrane
Glucose -D-Galactose-N-acteylglucodamine-D-glucose
Number of H antigen subtypes
4
H1, H2, H3, H4
Amount of H antigen (most to fewest)
O > A2 > B > A2B > A1 > A1B
Oh! Eto! Bhe! Eto Bhe! Ewan! Ewan Bhe!
RBC antigens are only synthesized on ___ precursor chains
Type 2
Enzyme in ABH antigens on red cells
a-2-L-fucosyltransferase by H gene
Substances secreted by A, B and H soluble substances
Glycoprotein
Secreted substances in A,B,H soluble substances are synthesized on ___ precursor chain
Type 1
Secretor (SeSe, Sese) is seen in ___ of random population
78%
Non secretor (sese) is seen in ___ of random population
22%
Naturally occurring antibody; production initiated at birth; predominantly IgM
ABO antibodies
Detectable titers of ABO antibodies _____
Peaks at ____
3-6 months
5-10 years
Principle of ABO typing technique
Hemagglutination
Using known sources of reagent antisera (anti+A, anti-B) to detect antigens on an individual’s red cells
Forward grouping
Checks the reaction of anti-A and anti-B reagents
Detects weak subgroups of A and B
Anti A, B
Principle for the test for determination of secretor status
Hemagglutination inhibition
Color of Anti-A reagent
Blue
Color of anti-B reagent
Yellow
Chemical preservatives of reagents
Sodium azide (0.1%)
Proteins present in plants that bind specifically to carbohydrate determinants and agglutinate erthrocytes through their cell surface oligosaccharide determinants
Lectins
Peanut extract
Arachis hypogaea
Soybean extract
Glycine soja
Using reagent cells with known A1 and B antigens testing the serum of the patient for ABO group antibodies
Reverse grouping
Human source; 4-5% RCS
Reagent A1 cells and B cells
hh genotype
No H antigens formed
Same phenotype as blood group O
Anti-A, anti-B, anti-A,B, and anti-H present in the serum
Bombay phenotype
Discovered by von Dungern/Dungren and Hirszfield in 1911
ABO subgroups
population frequency of people with A1 phenotype
80%
population frequency of people with A2 phenotype
20%
1-8% of A2 and 25% of A2B can form ___
Anti-A1
Mixed field agglutination with anti-A and or anti-A,B
A3
Weak agglutination with anti-A,B only
Ax
< or = red cells show very weak mf agglutination
Aend
No agglutination with anti-A and anti-A,B;
secretors demonstrate quantities of A substance in saliva
Am
No agglutination with anti-A and anti-A,B;
secretors contain small amount of A substance in saliva
Ay
No agglutination with anti-A and anti-A,B;
secretors contain only H substance and no A substance in saliva
Ael
Mixed field agglutination with anti-B and or anti-A,B
B3
agglutination with anti-A,B (wk/0 with anti-B)
Bx
no agglutination with with anti-B and anti-A,B;
secretors demonstrate quantities of B substance in saliva
Bm
No agglutination with anti-B and anti-A,B;
secretors contain only H substance and no B substance in saliva
Bel
weakly reacting or missing antibodies
Group I discrepancies
weakly reacting or missing antigens
Group II discrepancies
Occurs when bacterial enzymes modify immunodominant blood sugar A sugar (N-acetyl-D-galactosamine) into D-galactosamine which cross reacts with anti-B antisera
Acquired B phenomenon
resolution of acquired B phenomenon
Use monoclonal anti-B clone;
Treat RBCs using acetic anhydride
Resolution of Group I and II discrepancies
Use 2-5% RBCs;
Incubate sample and reagent at room temperature (20-24 deg C) for 15 - 30 mins –> if negative –> incubate at refrigerator temperature (4 deg C)
protein or plasma abnormalities resulting to rouleaux formation
Group III discrepancies
Resolution of Group III discrepancies
Wash RBCs with saline several times (6-8 washings)
refers to agglutination of altered RBCs by a large proportion of ABO-compatible adult human sera
Polyagglutination
passive adsorption of bacterial products: T, Th, Tk, Tx, Acquired B, VA
Microbially associated
mutation of hematopoietic tissue: Tn
Non-microbially associated
Confirmation of polyagglutination:
if RBCs show
1) agglutination with ___ and
2) No agglutination with ___
most adult sera;
cord sera
patient’s RBCs are agglutinated by ALL including OWN serum
Panagglutination
refers to inheritance of both AB genes form one parent carried on one chromosome and an O gene inherited from the other parent
Cis-AB
Resolution of group IV discrepancies due to cold antibodies
RBC: wash with saline at 37 deg C or use 0.01 M Dithiothreitol (DTT)
Serum: Warm at 37 deg C then read results at 37 deg C
Discovered the Rh blood group
Karl Landsteiner ans Alex Wiener
Primary cause of hemolytic disease of the fetus and the newborn (HDFN) and significant cause of HTR
Rh Blood group system
Based on the theory that 3 closely linked sets of alleles produced antigens in the system, each gene was responsible for producing a product or antigen on the red cell surface
Fisher Race
Postulated that the gene responsible for defining Rh actually produced an agglutinogen that contained a series of blood factors, in which each factor is an antigen recognized by an antibody
Wiener
number is assigned to each antigen of the Rh system in order of its discovery
Rosenfield
Codes for the presence or absence of D
RHD gene
Codes for the expression of the CcEE genes
RHCE gene
codes for Rh-associated glycoprotein
RHAG gene
Most common phenotype in Whites
R1r (31%)
Most common phenotype in Blacks
R0r (23%)
Rh phenotypes in Whites
R1 > r > R2 > R0
Rh phenotypes in Blacks
R0 > r > R1 > R2
Rh phenotypes in Asians
R1 > R2 > r > R0
Rh phenotypes with the MOST to LEAST amount of D antigen
D– > R2R2 > R1R1 > R1r or Ror > R1r’ or Ror’
Immunogenicity of Common Rh antigens
D > c > E > C > e