Blood Bank
Complete Study Guide
Question Answer
Monomer, best reacts at body temp, coats but does
IgG not directly lyse RBCs, induced by pregnancy and
transfusions, can cross the placenta
Pentamer, reacts best below body temp, binds
IgM complement and lyses RBCs, not induced by
pregnancy, can cross placenta
Low Ionic Strength Saline: Decreases repulsive charges
LISS between RBC (zeta potential), allowing them to get
closer together for greater antibody bridging
Draw back to using tends enhance expression of cold antibodies and
LISS autoantibodies
Decreases zeta potential. Used less commonly than
22 % Albumin
LISS
PEG Polyethylene Glycol: Excludes H2O and allows RBCs to
Page 1 of 24
, get closer during centrifugation. Generally greater
sensitivity than LISS or albumin
Tends to enhance expression of warm antibodies and
Draw back to using
autoantibodies. May lead to false positive reactions at
PEG
37°C from nonspecific agglutination
Tube testing:
Positives are usually IgM and insignificant if not ABO
Immediate Spin
Add potentiator if desired and incubate at 37°C • LISS
10-15 minutes • Albumin 15-30 minutes • PEG 15
Tube testing: 37°C
minutes DO NOT read at 37°C due to false positives •
No potentiation/saline 30-60 minutes
Tube testing: Wash to remove unbound globulins. Immediately add
Indirect antiglobulin antihuman globulin (AHG). Check cells if needed.
test (IAT) Antibodies reacting at IAT are more often significant
Antiglobulin test: Demonstrates in-vitro (outside the body) RBC coating
Indirect with antibody and or complement
Patient washed RBCs, then mixed with antihuman
Antiglobulin test:
globulin; demonstrates in-vivo (within the body) RBC
Direct (DAT)
coated with antibody and or complement
• Anti-IgG-C3 Polyspecific, most commonly used. •
Specific antiglobulin
Anti-IgG • Anti-C3-Cb
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, Some antibodies react more strongly with RBC
antigens that result from homozygous codominant
Dosage
gene expression resulting in “double-dose” antigen
expression
Most common
Kidd, Duffy, Rh, MNS
dosage
Proteolytic enzymes (ficin, papain) cleave RBC surface
glycoproteins. This may destroy certain RBC antigens
Enzymes
and may strengthen reactions by allowing antibodies
to bind better to previously shielded antigens
Enzymes that
Duffy, MNS Mr. Duffy's MNS are destroyed
destroy antigens
Enzymes that I, Kidd, Lewis, Rh I had a Kidd named Lewis with an Rh
enhance antigens problem
Certain substances when mixed with a red cell
antibody, inhibit the activity of that antibody against
Neutralization test red cells • ABO- Saliva (secretor) • Lewis- Saliva
(secretor for Leb) • P1- Hydatid cyst fluid and Pigeon
egg whites
Lectins Seed/plant extracts react with certain RBC antigens
A1 lectin Dolichos biflorus
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Complete Study Guide
Question Answer
Monomer, best reacts at body temp, coats but does
IgG not directly lyse RBCs, induced by pregnancy and
transfusions, can cross the placenta
Pentamer, reacts best below body temp, binds
IgM complement and lyses RBCs, not induced by
pregnancy, can cross placenta
Low Ionic Strength Saline: Decreases repulsive charges
LISS between RBC (zeta potential), allowing them to get
closer together for greater antibody bridging
Draw back to using tends enhance expression of cold antibodies and
LISS autoantibodies
Decreases zeta potential. Used less commonly than
22 % Albumin
LISS
PEG Polyethylene Glycol: Excludes H2O and allows RBCs to
Page 1 of 24
, get closer during centrifugation. Generally greater
sensitivity than LISS or albumin
Tends to enhance expression of warm antibodies and
Draw back to using
autoantibodies. May lead to false positive reactions at
PEG
37°C from nonspecific agglutination
Tube testing:
Positives are usually IgM and insignificant if not ABO
Immediate Spin
Add potentiator if desired and incubate at 37°C • LISS
10-15 minutes • Albumin 15-30 minutes • PEG 15
Tube testing: 37°C
minutes DO NOT read at 37°C due to false positives •
No potentiation/saline 30-60 minutes
Tube testing: Wash to remove unbound globulins. Immediately add
Indirect antiglobulin antihuman globulin (AHG). Check cells if needed.
test (IAT) Antibodies reacting at IAT are more often significant
Antiglobulin test: Demonstrates in-vitro (outside the body) RBC coating
Indirect with antibody and or complement
Patient washed RBCs, then mixed with antihuman
Antiglobulin test:
globulin; demonstrates in-vivo (within the body) RBC
Direct (DAT)
coated with antibody and or complement
• Anti-IgG-C3 Polyspecific, most commonly used. •
Specific antiglobulin
Anti-IgG • Anti-C3-Cb
Page 2 of 24
, Some antibodies react more strongly with RBC
antigens that result from homozygous codominant
Dosage
gene expression resulting in “double-dose” antigen
expression
Most common
Kidd, Duffy, Rh, MNS
dosage
Proteolytic enzymes (ficin, papain) cleave RBC surface
glycoproteins. This may destroy certain RBC antigens
Enzymes
and may strengthen reactions by allowing antibodies
to bind better to previously shielded antigens
Enzymes that
Duffy, MNS Mr. Duffy's MNS are destroyed
destroy antigens
Enzymes that I, Kidd, Lewis, Rh I had a Kidd named Lewis with an Rh
enhance antigens problem
Certain substances when mixed with a red cell
antibody, inhibit the activity of that antibody against
Neutralization test red cells • ABO- Saliva (secretor) • Lewis- Saliva
(secretor for Leb) • P1- Hydatid cyst fluid and Pigeon
egg whites
Lectins Seed/plant extracts react with certain RBC antigens
A1 lectin Dolichos biflorus
Page 3 of 24
