Recognizes the Presence of Multiple
Antigens on the Surfaces of Red Blood Cells that define
Blood Group Systems
Population Distribution of
Major Blood Groups
O Rh pos 38%
O Rh neg 7%
A Rh pos 34%
A Rh neg 6%
B Rh pos 9%
B Rh neg 2%
AB Rh pos 3%
AB Rh neg 1%
Compatibility testing is done to avoid hemolytic transfusion reaction
If the Host or Recipient recognizes the donor RBC surface antigens as foreign,
the host will mount an immune response to the donor RBC’s
Major Blood Groups
ABO
ABO blood group antigens present on red blood cells and IgM antibodies present in the serum.
Why do we have Anti-A or Anti-B Antibodies???
They are not present in the newborn
They develop in the first years of life
Exposure to plant, bacterial, viral antigens provokes this response
Why do we have Anti-A or Anti-B Antibodies???
Viruses transmitted from the respiratory tracts of humans to other humans drag along various antigens including ABO blood group antigens.
Prime the newborn’s immune system.
Reduces transmissibility of viruses within a population.
Rhesus
Rhesus Blood Group
The most significant is the
D antigen
Major Blood Groups
Rhesus
47 Antigens make up the
Rhesus Blood Group
The most significant is the
D antigen
There is no naturally occurring
Anti D
Production of Anti D in the
RH negative recipient
requires previous exposure
to the D antigen
(in utero or by transfusion)
If red cells are administered
to an ABO- or D-incompatible recipient,
the recipient will mount an
antibody response to the foreign
RBC surface antigens
IgM is polyvalent
and fixes complement
Intravascular Clumping of Donor RBC’s
Clumps and extruded RBC stroma
result in organ dysfunction
and possible death
Incidence 1:38,000 – 1:70,000
Mortality 1:30
Other Blood Groups
No naturally occurring antibodies
Immune response requires
previous exposure
Weaker titers of univalent antibodies
Donor RBC’s coated with host antibodies
Image
Stiffer RBC membrane
Susceptible to attack by
splenic macrophages
But no
intravascular clumping
Bits of Donor RBC membrane
lost traversing splenic sinusoids
(extravascular hemolysis)
Spherocytes
Decreased RBC survival
Delayed anemia
Priming for worse reaction
Donor
Questionnaire:
Medical history
Lifestyle
Finger stick:
Checking Hct
Donor
Needs a Hct of 0.38
A drop of donor blood is placed into a
test tube containing a
CuSo4 solution
CuSo4 solution has a SG of 1.053
RBC with Hct > 0.38 sink to
the bottom of the test tube
Donor
Side sample (20cc) collected for testing:
Blood group and Infection
The bag is anticoagulated
The unit is labeled with a lot#
like any drug
e.g. LH59321
DIFFERENT LEVELS OF COMPATIBILITY TESTING
COMPATIBILITY TESTING
The purpose of pre-transfusion compatibility testing is to PREVENT hemolytic transfusion reaction
Clerical and technical components
Samples must be labeled at the bedside
Two methods of ID required:
Name, SSN, MR#, DOB
The phlebotomist must sign the tube
COMPATIBILITY TESTING
Lab checks:
Identity
Record of previous specimen
Record of previous ABO-Rh type
History of abnormalities
COMPATIBILITY TESTING
]
Processing the specimen:
ABO Group determined (forward and reverse)
D typing determined
Antibody screen will be performed
ABO/Rh identical or compatible blood will be made available
ABO TYPING
Front or forward type using monoclonal anti-A and anti-B (commercial)
The sample is diluted to Hct 0.08, the commercial antibodies added & the test tube is centrifuged
The RBC’s are then examined for clumping (gross observation, gel suspension)
Anti A Anti B Anti A Anti B
A IMAGE B
Anti A Anti B Anti A Anti B
AB O
Back or reverse type with A and B cells
Commercially available A and B cells are added to two tubes of plasma
AB B A O
IMAGE
How do we know whether or not the host (or recipient) has antibodies to minor blood group antigens?
Add commercial RBC’s with known important minor antigens on their surface to host (or recipient) plasma and centrifuge. Then incubate at body temperature for 15-30 minutes
Then add rabbit antiglobulin
If recipient antibodies have coated
commercial RBC surfaces
IMAGE
Possibly significant minor blood groups
MNS 002 37
P P1 003 1
RH RH 004 47
LUTHERAN LU 005 18
KELL KEL 006 21
LEWIS LE 007 3
DUFFY FY 008 6
KIDD JK 009 3
DIEGO DI 010 2
CARTWRIGHTYP 011 2
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