PRELIM LABORATORY L3: ABO TYPING Flashcards
reagents used in forward typing
EDTA Blood Sample
Anti-A sera
Anti-B sera
where antigens are found
Surface of RBC
where antibodies are found
serum/plasma
principle of forward typing
detects the antigens present in person’s RBCs
what does anti-sera contain?
immunoglobulins specific to an antigen
determine the blood type (FT):
presence of agglutination on A and no agglutination on B
type A
determine the blood type (FT):
absence of agglutination on A and presence of agglutination on B
type B
determine the blood type (FT):
absence of agglutination on both A and B
type O
determine the blood type (FT):
agglutination on both A and B
type AB
reagents used in reverse typing
0.85-0.90% NSS
3-5% RCS (KA, KB, KO, KAB)
principle of reverse typing
detects the antibody present in px or donor’s serum by using a reagent red cell of known specificity
other terms for reverse typing
backward typing
indirect typing
serum typing
T or F:
in every tube method, always add first the clear solution
T
determine the blood type (RT):
no agglutination on known A
agglutination on B, AB, O
type A
determine the blood type (RT):
no agglutination on known B
agglutination on A, AB, O
type B
determine the blood type (RT):
no agglutination on known O
agglutination on A, AB, B
type O
determine the blood type (RT):
no agglutination in all tubes
type AB
What is the purpose of performing both forward and backward typing?
To cross-check and confirm the blood type for accuracy and prevent errors in transfusion. (reverse typing is confirmatory test)
interpret the grading:
+4
single clump of agglutination with no free cells
interpret the grading:
+3
three or four individual clumps with few free cells
interpret the grading:
+2
many fairly large clumps with many free cells
interpret the grading:
+1
fine granular appearance visually, but definite small clumps (10-15) cells per LPF
interpret the grading:
+W
2-3 cells sticking together in LPF, uneven distribution, visually no agglutination
interpret the grading:
“-”
hemolysis (partial or total) must be interpreted as positive
H
all cells are free
N-lectin plant
Vicia graminea
