Blood Bank - Week 1 (Ag/Ab, Antiglobulin, ABO) Flashcards
Which part of the IgG antibody allows it to cross the placenta?
Fc (crystallizable region)
Naturally occuring Abs
Antibodies against antigens in nature that are very similar to antigens on RBC’s
Which are the expected antibodies in blood?
Anti-A and anti-B
Which antibody can have levels that fall below the detectable level?
Kidd’s
What is the method used for in-vivo sensitization detection?
DAT (direct antiglobulin test)
Take blood sample, incubate with antibodies to human IgG and C3, look for agglutination
What is the method used for in-vitro sensitization detection?
IAT (indirect antiglobulin test)
Take patient serum, add RBC’s with known antigens, incubate with antibodies to human IgG, look for agglutination
What factors influence Ag/Ab reactions?
Centrifugation, Ag-Ab ratio, pH, temp
What is in polyspecific AHG (antihuman globulin reagent)?
Antibodies against IgG and C3d (complement)
What is in monospecific AHG (antihuman globulin reagent?
Only antibodies against IgG
Why do we incubate RBC’s with antisera?
To allow time for the antibody to attach to the RBC antigen
Why do we perform at least 3 saline washes?
Remove free globulin molecule
Why do we add antiglobulin reagent?
To form visual RBC agglutinates in positive reactions
Why do we centrifuge?
Brings cells closer together so they can agglutinate if positive
Why do we add antibody-coated RBC’s to negative reactions?
To confirm washing and reagents worked correctly
What do we do for sample with Rouleaux (too much protein in blood)?
Wash sample to remove protein
If you have a positive DAT (in-vivo) what will your auto control (patient plasma and cells) be?
Positive
A1 reacts with:
Anti-A and anti-A1, agglutinates with lectin
A2 reacts with:
Anti-A only, increased reactivity with anti-H lectin
What could cause you to suspect a patient is A2?
If the forward type is weaker A and the reverse is O (Anti-B and some anti-A1)
What is the sugar of the A antigen?
N-acetylgalactosamine
What is the sugar of the B antigen
D-galactose
What blood can be given to Bombay patients?
Other Bombay blood
What blood can be given to A2 blood?
A2 or O
Rank blood types from greatest amount of H substance to least amount of H substance
O > A2 > B > A2B > A1 > A1B
Why do we add clear solutions first and cells second?
Once you add cells it can be hard to see if you added clear solutions, so add them first to be sure
What health conditions could cause ABO reverse discrepancies?
Depressed antibody production (elderly, hypogammaglobulinemia, immunodeficiency, etc)
What health conditions could cause ABO forward discrepancies?
Weakly reacting/missing antigens (“acquired B” phenomenon, leukemia, Hodgkin’s disease, etc)
What is “acquired B” phenomenon?
Bacterial enzymes modify A sugar into sugar similar to B (acidify to see if it is true B)
What could cause discrepancie between forward and reverse?
Protein/plasma abnormalities (treat by washing), cold reactive antibodies, warm autoantibodies, etc
Rank Rh antigens from greatest immunogenicity to least
D > c > E > C > e
Weiner terminology of DCe
R1
Weiner terminology of DcE
R2
Weiner terminology of Dce
R0
Weiner terminology of DCE
Rz
Weiner terminology of dce
r
Weiner terminology of dCe
r’
Weiner terminology of dcE
r”
Weiner terminology of dCE
ry
Room temp IS antibodies
M, N, P1, Le(a), Le(b), Lu(a)
Not clinically significant, IgM
37C incubation antibodies
D, E, K
IgG, clinically significant
Antiglobulin (AHG) phase antibodies
Rh, K, Duffy, Kidd, S, s, Lu(b)
IgG, clinically significant
