-Complement bound all the way to MAC formation = hemolysis
immunoglobulin associated with extravascular hemolysis - Correct Answer IgG
- complement stops at C3b-no MAC formation
Antigens are found on - Correct Answer - RBCs
-WBCs
- plts
Antigenicity based on - Correct Answer - Chemical composition & complexity.
- Degree of foreignness.
- Molecular weight (size).
- Dosage & antigen density.
- Route of administration
Protein antigens - Correct Answer - produced as part of membrane
- gene codes for protein which is the antigen
- well developed at birth
- antigens found on RBCs usually unique to only those cells
- Rh, Kidd, Duffy, S, s
Carbohydrate antigens - Correct Answer - ABO, Lewis, H, I, i, M, P1
- not well developed at birth
- gene codes for enzyme that adds sugar to precursor substance on RBC membrane
- antigens are very similar in structure to those found in nature on some pollen or bacterial membranes
,IgG will frequently cause in vivo hemolysis due to: - Correct Answer antibody coating the red blood cells
IgM will not cause in vivo hemolysis with the exception of: - Correct Answer ABO antibodies
immunoglobulin serum concentration - Correct Answer G > A > M > D > E
only immunoglobulin capable of placental transfer - Correct Answer IgG
hemolysin - Correct Answer
antigen
Naturally Occurring antigen exposure - Correct Answer - Exposure to antigens found on bacteria or
pollen, particles similar to RBC antigens
- Antibody production can happen after birth & throughout life
red cell immune antigen exposure - Correct Answer -Antibody production after exposure to antigen on
foreign RBC:
-Through transfusion of donor RBC
-Through pregnancy
prozone - Correct Answer - antibody excess ("B comes before G")
-linkages between cells; no
agglutination
zone of equivalence -
formed
post zone - Correct Answer - antigen excess ("G after B")
- - any agglutination is hidden by masses of unagglutinated antigens
,Washing Red Blood Cells Before Making the 3-5% Suspension - Correct Answer The purpose of washing
the red blood cells is to remove plasma, which contains substance that may interfere with antigen-
antibody reaction
If a patients cells have the antigen: - Correct Answer the antibody should NOT be present in that serum
If an antibody to a blood group antigen is present in the serum of a patient: - Correct Answer their cells
should lack that antigen
Too much serum = - Correct Answer false negative
Very weak positive reaction - Correct Answer increase the serum to provide more immunoglobulin
molecules and give a stronger reaction
potentiators - Correct Answer - enhance in vitro agglutination
- sometimes only sensitization occurs, something extra needs to be added to reduce zeta potential and
make agglutination visisble
- Albumin
- weak IgG Abs
enzyme potentiators -
ions with some antigens
immediate spin technique -
les cause visible agglutination of antigen-positive RBCs
suspended in saline.
- Direct agglutination can be observed
, Antiglobulin Test Principle - Correct Answer - used to detect clinically significant unexpected antibodies
that have coated cells either in vivo or in vitro
- Red cells coated 'sensitized' with complement or IgG antibodies do not produce visible agglutination
with antigen-positive RBCs suspended in saline
-In order for agglutination to occur an additional antibody, which reacts with the Fc portion of the IgG
antibody, or with the C3b or C3d component of complement, must be added to the system.
- This will form a "bridge" between the antibodies or complement coating the red cells, causing
agglutination
Antiglobulin Reagent - Correct Answer
goat, mouse)
nstant region' or the Fc portion not the variable region
polyclonal vs monoclonal antiglobulin - -human Globulin: blend of
Anti-IgG & Anti-C3b, -C3d
-IgG alone or Anti-C3b,-C3d alone
AHG - Anti-Human Globulin - Correct Answer - has all of the same characteristics of an antigen
- used in lab testing to detect the presence of antibody sensitized RBCs in Vitro
- indirect antiglobulin test
- AHG will react with the bound antibody and 'convert' sensitization to agglutination
Direct Antiglobulin Test (DAT): - Correct Answer Detects IgG antibodies or complement coating patient's
cells 'in vivo'
Indirect Antiglobulin Test (IAT): - Correct Answer Detects IgG antibodies or complement that has
attached to the red cell membrane 'in vitro'