DIRECT BLOOD TYPING Flashcards
It is the process of testing of blood sample to determine an individual’s blood group.
Blood Typing
Blood Typing uses what?
Commercially prepared antisera (forward) or Known Red Cell Suspension (Reverse)
What rules are applied in blood typing?
Rules of Specificity
What are the TWO Rules of Specificity?
- If the antigen is SPECIFIC to the antibody, there is always a + reaction
- If the antigen is NON-SPECIFIC to the antibody, there is NO reaction
If the antigen is specific to the antibody, what is the reaction produced?
A positive reaction
If the antigen is NON specific to the antibody, what is the reaction produced?
NO REACTION
What are the methods of Blood Typing?
- Slide method
- Tube method
This method is used for rapid blood typing
Slide method
This is method is used for routine blood typing
Tube method
This method is used for bed-side typing
Slide method
This method is only performed for FORWARD/DIRECT BLOOD TYPING
Slide method
This method is used when BOTH forward and reverse typing are performed
Tube method
This method involves centrifugation
Tube method
This method is the “screening procedure”
Forward/Direct/Cell Grouping
What is the principle in Forward/Direct/Cell Grouping?
To detect unkown antigen using commercially prepared typing sera
What is the reagent used in Forward/Direct/Cell Grouping?
Commercially prepared typing sera that has 1:256 potency level
What is the potency level of the commercially prepared typing sera used in forward/Direct/Cell Grouping?
1:256
it is the relative strength of the antibody present in
the reagent.
Potency level
Principle: To detect unknown antigen using commercially prepared typing
sera. Which Blood Typing Method does this principle apply to?
Forward/Direct/Cell Grouping
It is the source of monoclonal anti-A antibody
Blood type B serum
It is the Coloring agent/dye for Anti-A typing serum
BLUE DYE
What are examples of blue coloring agents?
- Thymol blue
- Bromphenol blue
- Phenol blue
- Patent blue
- Trypan blue
used as a preservative in typing sera.
0.1 Sodium azide
It has an antimicrobial properties that prevents the growth of microorganisms in
the typing serum.
0.1 Sodium azide
It is the source of monoclonal anti-B antibody
Blood type A serum
It is the Coloring agent/dye for Anti-B typing serum
YELLOW DYE
What are examples of yellow coloring agents?
- Acriflavin yellow
- Tartrazine yellow
What are examples of yellow coloring agents?
- Acriflavin yellow
- Tartrazine yellow
Reagents in forward blood typing have 3 utilities. What are they?
- Detects A and B antigens
- useful in ABO subgroupings
- Used as control in forward typing
Reagents in forward blood typing may be used as a control
True or False
TRUE
If reagents in forward typing is used as a CONTROL:
What must the result be If Anti A and/or Anti B is POSITIVE?
Anti AB should be POSITIVE
If reagents in forward typing is used as a CONTROL:
What must the result be If Anti A and/or Anti B is NEGATIVE?
Anti AB should be NEGATIVE
If reagents in forward typing is used as a CONTROL:
What must the result be If Anti A and/or Anti B is NEGATIVE?
Anti AB should be NEGATIVE
What is the source of polyclonal anti-AB antibody?
“O” Serum
Forward Blood Typing Procedure
What is the recommended measurement of the tubes used for this procedure?
10 or 12 x 75 mm tubes
Forward Blood Typing Procedure
The tube may be left at the room temperature for five minutes before centrifugation
True or False
TRUE
Forward Blood Typing Procedure
Tubes may be spun at once 1000-2000 r.p.m. for 2 minutes
True or False
1 minute
FALSE
Forward Blood Typing Procedure
As an alternative to centrifugation, sedimented cells may be read after
standing 30 mins at room temperature, but this is less specific
True or False
1 hour at room temp; less sensitive
FALSE
Forward Blood Typing Procedure
Tube is to be read under the low power of the microscope
TRUE OR FALSE
TRUE
It will also detect the weakly reacting subgroups of A
Forwad Blood Typing
NOT SURE ETO
This is used to confirm group O blood and to identify rare subgroups of A.
Forward Blood Typing
NOTE SURE ETO
This antiserum will agglutinate cells of groups A, B and AB, but not group O.
Forward Blood Typing: Test Tube method
NOT SURE ETO
This antiserum will agglutinate cells of groups A, B and AB, but not group O.
Forward Blood Typing: Test Tube method
NOT SURE ETO
This procedure uses a flat slide and red cells from clotted or anti coagulated
blood
Forward Blood Typing: Slide Method
How many percent of saline suspension of red cells must be prepared in a forward typing slide method?
10% saline suspension
For forward typing slide methods, agglutination may be weakened at temperatured above what?
above 22 degC
