MMSC 420 Exam 1 Questions and Answers Latest Update 2025
Group A - Answers Anti-B
A antigen
Group B - Answers Anti-A
B antigen
Group AB - Answers None
A and B antigens
Group O - Answers Anti-A and Anti-B and Anti-A,B
None
A typing - Answers 4+ 0 4+ 0 4+
B typing - Answers 0 4+ 4+ 4+ 0
AB typing - Answers 4+ 4+ 4+ 0 0
O typing - Answers 0 0 0 4+ 4+
A2 - Answers -most common subgroup
*20% of people have*
-usually not detected unless Anti-A1 is present
-can cause ABO typing discrepancies if Anti-A1 is produced
Resolution for A2 - Answers -type pt RBCs with Anti-A1 lectin and test pt plasma with reagent
A2 cells
if pt is A2 with anti-a1 in plasma - Answers pt RBCs do NOT react with anti-a1 lectin
Do all A1 individuals produce anti-a2 ab - Answers no only 1-8% do
do all A2 individuals produce anti-a1 ab - Answers no only 22-33% do
is anti-a1 significant - Answers if reacts at 37 degrees C yes
is anti-a1 immune stimulated - Answers no its naturally occuring
weak agglutination - Answers could be A3 (mixed field with anti-a), Aend (weak agglutination,
mixed field with anti-a), or Ax (negative with anti-a, positive with anti-a,b)
, No agglutination - Answers Am (negative with anit-a but elution is positive for A), Ay (same as
Am but ads/elu studies are weaker), Ael (same as Am and Ay but may produce anti-a that reacts
with a2 cells as well as a1 cells)
absorption - Answers bind ab to cell
elution - Answers cleave bound ab
Acquired B antigen - Answers -associated with carcinoma of the colon or rectum, infection with
gram-neg organisms and intestinal obstruction
-phenotype arises through the modification of the A antigen by microbial enzymes called
deactylases
preanalytical error - Answers -incorrect ID of patient
-incorrect labeling of specimen
-sample mix up
analytical error - Answers -clinical errors (labeling tubes, transcription)
-cell suspension too heavy or too light
-failure to add reagents to patient serum
-failure to follow manufactures instructions
-failure to note hemolysis
-uncalibrated centrifuge
-contaminated reagents
-centrifugation problems
-improper resuspension of cell button
-mix up samples
ABO discrepancies - Answers -most common in reverse grouping
-due to weakly reacting or missing antibodies
other reasons for discrepancies - Answers -newborns don't produce antibodies until 4-6 months
of age
-elderly patients
Group A - Answers Anti-B
A antigen
Group B - Answers Anti-A
B antigen
Group AB - Answers None
A and B antigens
Group O - Answers Anti-A and Anti-B and Anti-A,B
None
A typing - Answers 4+ 0 4+ 0 4+
B typing - Answers 0 4+ 4+ 4+ 0
AB typing - Answers 4+ 4+ 4+ 0 0
O typing - Answers 0 0 0 4+ 4+
A2 - Answers -most common subgroup
*20% of people have*
-usually not detected unless Anti-A1 is present
-can cause ABO typing discrepancies if Anti-A1 is produced
Resolution for A2 - Answers -type pt RBCs with Anti-A1 lectin and test pt plasma with reagent
A2 cells
if pt is A2 with anti-a1 in plasma - Answers pt RBCs do NOT react with anti-a1 lectin
Do all A1 individuals produce anti-a2 ab - Answers no only 1-8% do
do all A2 individuals produce anti-a1 ab - Answers no only 22-33% do
is anti-a1 significant - Answers if reacts at 37 degrees C yes
is anti-a1 immune stimulated - Answers no its naturally occuring
weak agglutination - Answers could be A3 (mixed field with anti-a), Aend (weak agglutination,
mixed field with anti-a), or Ax (negative with anti-a, positive with anti-a,b)
, No agglutination - Answers Am (negative with anit-a but elution is positive for A), Ay (same as
Am but ads/elu studies are weaker), Ael (same as Am and Ay but may produce anti-a that reacts
with a2 cells as well as a1 cells)
absorption - Answers bind ab to cell
elution - Answers cleave bound ab
Acquired B antigen - Answers -associated with carcinoma of the colon or rectum, infection with
gram-neg organisms and intestinal obstruction
-phenotype arises through the modification of the A antigen by microbial enzymes called
deactylases
preanalytical error - Answers -incorrect ID of patient
-incorrect labeling of specimen
-sample mix up
analytical error - Answers -clinical errors (labeling tubes, transcription)
-cell suspension too heavy or too light
-failure to add reagents to patient serum
-failure to follow manufactures instructions
-failure to note hemolysis
-uncalibrated centrifuge
-contaminated reagents
-centrifugation problems
-improper resuspension of cell button
-mix up samples
ABO discrepancies - Answers -most common in reverse grouping
-due to weakly reacting or missing antibodies
other reasons for discrepancies - Answers -newborns don't produce antibodies until 4-6 months
of age
-elderly patients
