Test #2 Immunohematology Chapters 8 & 9 UPDATED ACTUAL Questions and
CORRECT Answers
What class are the majority of immunoglobulins? the majority are IgG
Which Ag is related with mycoplasma pneumoniae? I (develop a cold antibody to specify to I antigen)
what are the cold agglutinins group antibodies? Best react at 4C :
Lewis
H
I
P1
M&N
What check cells are and why we add check cells Are IgG sensitized RBC's cells that we added to ensure that AHG was capable of
(Coombs control) to all reactions? a reaction (or if AHG is functioning) and cells are adequately washed.
Check cells are cells coated with IgG and should react positively with the AHG in the tube. If
check cells are negative, the procedure was not performed correctly and should
be repeated.
agglutination definition The dumpling together of red blood cells or any particle matter resulting from
interaction of antibody and its corresponding Ag.
Red cell button entirely resuspended and not visible Negative (0)
agglutination
Red cell button entirely resuspended with many small 1+
aggregates present
Red cell button entirely resuspended with several 2+
medium sized aggregates present, clear supernatant
, Red cell button entirely resuspended with few medium to 3+
large sized aggregates present, clear supernatant
Red cell button entirely resuspended with one large 4+
sized aggregate present, clear supernatant
Is associated with Paroxysmal Cold Hemoglobinuria? Anti-P
What Ab or Ag react below of 37C, called media spin , Lewis
cold, room temp? H
I
P1
M&N
Which Ab react best at AHG phase? IgG and few IgM
Rh Anti-I
kell Anti-Lea
Duffy Anti-Leb
Kidd
M(some)
Immediate Spin (IS) Patient serum or plasma and reagent red cells are combined, then centrifuged,
and observed for agglutination. Enhancement media such as albumin, LISS or
PEG, can be added.
37C Incubation The tubes are incubated at 37°C for 15-60 minutes, depending on the
enhancement media used. After the incubation period, the tubes are centrifuged
and observed for agglutination. The cells are washed 3-4 times to remove any
unbound antibody. This is an important step in the tube method. Improper
washing may lead to false-negative results.
Indirect antiglobulin test or Anti-human globulin (AHG) AHG is then added, the tubes are centrifuged, and are observed for agglutination.
Check cells are added to all negative tubes. Check cells are cells coated with IgG
and should react positively with the AHG in the tube. If check cells are negative,
the procedure was not performed correctly and should be repeated.
Immediate spin: Antibodies reacting in this phase tend to be cold reactive. They are usually IgM
class and not clinically significant (with the exception of the A and B antibodies).
37°C: Antibodies that react in this phase include strong IgM or IgG antibodies. After
incubation, the tubes are examined for the presence of hemolysis. If complement
was bound during incubation then hemolysis could be seen. NOTE: This reaction
would only occur in serum samples. If EDTA plasma samples are used for testing,
the complement cascade has been halted. Magnesium and calcium ions are not
available for complement to be activated.
CORRECT Answers
What class are the majority of immunoglobulins? the majority are IgG
Which Ag is related with mycoplasma pneumoniae? I (develop a cold antibody to specify to I antigen)
what are the cold agglutinins group antibodies? Best react at 4C :
Lewis
H
I
P1
M&N
What check cells are and why we add check cells Are IgG sensitized RBC's cells that we added to ensure that AHG was capable of
(Coombs control) to all reactions? a reaction (or if AHG is functioning) and cells are adequately washed.
Check cells are cells coated with IgG and should react positively with the AHG in the tube. If
check cells are negative, the procedure was not performed correctly and should
be repeated.
agglutination definition The dumpling together of red blood cells or any particle matter resulting from
interaction of antibody and its corresponding Ag.
Red cell button entirely resuspended and not visible Negative (0)
agglutination
Red cell button entirely resuspended with many small 1+
aggregates present
Red cell button entirely resuspended with several 2+
medium sized aggregates present, clear supernatant
, Red cell button entirely resuspended with few medium to 3+
large sized aggregates present, clear supernatant
Red cell button entirely resuspended with one large 4+
sized aggregate present, clear supernatant
Is associated with Paroxysmal Cold Hemoglobinuria? Anti-P
What Ab or Ag react below of 37C, called media spin , Lewis
cold, room temp? H
I
P1
M&N
Which Ab react best at AHG phase? IgG and few IgM
Rh Anti-I
kell Anti-Lea
Duffy Anti-Leb
Kidd
M(some)
Immediate Spin (IS) Patient serum or plasma and reagent red cells are combined, then centrifuged,
and observed for agglutination. Enhancement media such as albumin, LISS or
PEG, can be added.
37C Incubation The tubes are incubated at 37°C for 15-60 minutes, depending on the
enhancement media used. After the incubation period, the tubes are centrifuged
and observed for agglutination. The cells are washed 3-4 times to remove any
unbound antibody. This is an important step in the tube method. Improper
washing may lead to false-negative results.
Indirect antiglobulin test or Anti-human globulin (AHG) AHG is then added, the tubes are centrifuged, and are observed for agglutination.
Check cells are added to all negative tubes. Check cells are cells coated with IgG
and should react positively with the AHG in the tube. If check cells are negative,
the procedure was not performed correctly and should be repeated.
Immediate spin: Antibodies reacting in this phase tend to be cold reactive. They are usually IgM
class and not clinically significant (with the exception of the A and B antibodies).
37°C: Antibodies that react in this phase include strong IgM or IgG antibodies. After
incubation, the tubes are examined for the presence of hemolysis. If complement
was bound during incubation then hemolysis could be seen. NOTE: This reaction
would only occur in serum samples. If EDTA plasma samples are used for testing,
the complement cascade has been halted. Magnesium and calcium ions are not
available for complement to be activated.
