The document discusses different types of blood compatibility testing (cross-matching). It describes standard cross-matching which involves testing donor blood against recipient serum in saline, albumin, and anti-human globulin tubes to detect antibodies. Emergency and rapid cross-matching are also summarized, which involve fewer tests and are only used in urgent situations. The purpose of cross-matching is to select donor blood that will not cause adverse reactions in the recipient.
2. Content
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7.1. Cross matching
7.2. Types of Cross Match
7.3. Steps for compatibility testing
7.4. Choice of Blood for cross-match
7.5. Procedure for cross-match
7.5.1.Standard cross matching
7.5.2. Emergency cross matching
7.5.3. Rapid slide crossmatching
3. Learning Objectives
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At the end of this chapter, the student should be
able to:
Understand the cross-match and its primary
purpose.
Explain the constituents of the major and
minor cross match.
Select appropriate blood for cross-match.
Describe the types of antibodies that can be
encountered at various phases of a cross-
match.
4. 7.1 Cross-Matching
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It is a procedure performed before transfusion to
select donor’s blood that will not cause any
adverse reaction, (hemolysis /agglutination)
It helps the patient to receive maximum benefit
from the transfusion of red cells
This is done by ensuring compatibility
5. Cross-Matching…
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Will:-
Verify donor cell ABO compatibility
Detect most antibodies against donor cells
Will Not:-
Guarantee normal survival of RBCs
Prevent patient from developing an antibody
Detect all antibodies
Prevent delayed transfusion reactions
Detect ABO/Rh errors
Types of Cross Match
Two types
I. Major cross-match:
Involves mixing recipient’s serum with the donor’s red cells.
is much more critical for assuring safe transfusion than the minor
compatibility test.
called major b/c the Abs in the recipient’s serum are most likely to
6. Types….
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II. Minor cross match:
Involves mixing the donor’s serum with
patient’s red cells
Called minor because
any Ab in the donor’s serum will be diluted by the
large volume of the recipient’s blood
the destructed RBCs of the patient may be
compensated by the transfused RBC of the donors
7. 7.3. Steps for compatibility testing
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Accurate Patient Identification
Proper sample collection and handling
Review of the recipient’s past blood bank records
Careful ABO/Rh determination
Antibody screening of the recipient (cross matching of
the donor unit).
In cases when the recipient possess a clinically
significant Antibody, donor units must be:
Screened for the corresponding Ag and should be
negative
Cross- matched
8. Steps for….
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Finally, during the actual transfusion :
careful observation of the recipient’s vital signs and
post transfusion hematocrit and Heamoglobin levels
must be considered.
9. 7.4.Choice of Blood for cross-match
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The blood selected for cross-match should be of the same ABO
and Rh (D) group as that of the recipient.
However, Rh positive recipients may receive either Rh positive
or Rh negative blood.
Whenever possible blood of the patients own blood group
should be given.
Otherwise the following rules should be applied.
Group A patient.
Should receive group A blood, if not available group O
Group B patient.
10. Choice of…
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Group O patient.
Can only receive group O blood
Group AB patient.
Should receive from group AB, if not possible can receive
blood from group A,B, and O.
When cross-matching is carried out, the serum is tested
against the cells.
The serum should be fresh, that is not more than 48hours
old, to make sure that it contains complement.
11. Choice of…
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When deciding on methods for cross-matching, the
following conditions are required for Ag-Ab reactions.
The right Temperature.
Suitable surrounding medium
Antigen-Antibody ratio etc..
The safe cross-matching of blood requires that the
donor’s cells be mixed with the patient’s serum in three
separate tubes, using :
1. Saline
2. Albumin
3. Anti-human globulin reagents
12. 1. Saline tube
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The red cells from the donor are suspended in
saline and mixed with the patient’s serum .
show the presence of any complete antibodies
Agglutination in the saline tube is usually caused
by:
anti-A or anti-B antibodies and
Occasionally by Lewis, MNSs, Lutheran and kell
antibodies.
13. 2. Albumin tube
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The red cells from the donor’s suspended in
saline, are mixed with the patient’s serum,
and albumin is added.
The tube is incubated at 370C
shows the presence of any incomplete
antibodies
the antibodies react in albumin or any other
protein medium
Agglutination in the albumin tube is often
caused by:
the rhesus antibodies,
Lewis, MNSs, Lutheran and P antibodies, and
occasionally by anti-kell.
14. 3. Anti-human globulin tube
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A more concentrated suspension of red cells
is mixed with the patient’s serum and
incubated at 370C and then AHG is added.
A positive test detects the presence of
antibodies of:
rhesus, kell, kidd, S and Lewis
Anti globulin is also essential for detection
anti-Duffy
15. 7.5. Procedure for cross-match
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7.5.1.Standard cross-match
Is cross-match that is performed in three tubes
(Saline, albumin and AHG) within 45 to 60
minutes
Clinical significance
detects unexpected (irregular) antibodies in the
recipient/ donor serum
16. Cross match (Standard)…
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Principle
Serum of the recipient / donor is tested
against the red cells of the donor/ recipient
under different conditions in order to establish
their compatibility
Type of specimen
Serum (plasma) not older than 48 hrs
Washed cells (20-30% and 2-5%)
17. Cross match (Standard)…
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Equipments and reagents
Test tubes
Centrifuge
Microscope
Microscopic slide
Normal saline
20% albumin
AHG (Coombs reagents)
18. Procedure
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1. Take 3 small tubes mark them 1,2 and 3, and add to
each the following
Tube 1 1volume of patient’s serum
1volume of 3-5% donor’s red cells
Tube 2 1 volume of 20% bovine albumin
1volume of patient’s serum
1volume of 3-5% donor’s red cells
Tube 3 3 volume of patent’s serum
1volume of 20-30% suspension of
donor’s cells
19. Cross match (Standard)…
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2. Incubate tube 1 and 2 for 30 minutes at 370C.
Incubate tube 3 for 15 minutes at 370C.
3. After incubation, remove tube 3 and wash the
cells three times with clean saline to make
sure that all the globulins are removed
from the cells.
4. And make a 3% saline suspension of the
washed cells in a tube.
20. Cross match (Standard)…
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5. To one volume of red cell deposit add 2
volumes of fresh diluted antiglobulin (coombs)
Reagent.
6. Remove tube 1 and 2 and centrifuge with
tube 3 for one minute at 1000 rpm
7. Examine the tube for heamolysis
macroscopically and microscopically for
agglutination.
21. Cross match (Standard)…
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Results
No hemolysis or agglutination is seen in tube
1, 2 or 3
the blood is compatible and can be issued with the
completed cross-match label.
If there is agglutination or hemolysis in any of
the tubes
the blood is incompatible, and must not be issued
for the patient.
22. Incompatibility investigation
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ABO incompatibility (anti A and Anti-B.)
Saline tube ………………….Shows strong
agglutination
Albumin tube ………………. Shows agglutination
Anti- globulin tube ………… show no agglutination
Rhesus incompatibility (anti-D ,c, e)
Saline tube …………………….does not usually show
agglutination
Albumin tube …………………. Shows agglutination
Anti- globulin tube ……………. Shows agglutination
23. Cross match (Incomp. Invest.)…
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Anti- Duffy and anti- kidd incompatibilities
Saline tube …… Does not usually show agglutination
Albumin tube … does not usually show agglutination
Anti- globulin tube ……………. Shows agglutination
Anti- Lewis incompatibility
Saline tube …………………….. Shows agglutination
Albumin tube ………………….. Shows agglutination
Anti- globulin tube ……………. Shows agglutination
24. 7.5.2 Emergency cross match
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Performed when there is no enough time to perform the
standard cross match
Takes about 25 to 30 minutes and
Does not include antiglobulin test.
Principle
Serum of the recipient / donor is tested against the red
cells of the donor/ recipient in saline and albumin medium
in order to establish their compatibility
Type of specimen
Serum (plasma) not older than 48 hrs
Washed cells (2-5%)
26. Procedure:
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1. Take 2 small tubes, mark them 1 and 2 and
add to each the following
Tube 1 1volume of patient’s serum
1volume of 3-5% donor’s red cells
Tube 2 1volume of patient’s serum
1volume of 3-5% donor’s red cells.
1volume of 20% bovine albumin
27. Cross match (Emergency)…
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2. Leave tube 1 at room temp for 15 minutes
incubate tube 2 for 15 minutes at 370C.
3. Centrifuge both tubes for one minute at 1000
rpm/min
4. Examine the tubes macroscopically for
hemolysis and microscopically for agglutination.
28. Cross match (Emergency)…
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Results
If no hemolysis or agglutination is seen in either
tube 1 or 2
the blood is compatible and can be issued with the
emergency cross match.
If agglutination or hemolysis is seen in either of
the tubes
the blood is incompatible and must not be issued for the
patient.
29. 7.5.3. Rapid direct slide cross match
(Request for un cross matched blood )
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Takes only 3 or 4 minutes
Plasma is used instead of serum.
Not safe and must only used in extreme emergencies
Standard cross match should be carried out while the
transfusion is in progress.
Procedures
1. Take 2 volume of patient’s plasma on a slide
2. Add 1 volume of donor’s whole blood of the same
group as the patient and mix.
3. Leave for 2 minutes and examine microscopically
for agglutination
Results. If the cells show agglutination the blood must
not be given and will usually indicate that the wrong
ABO group blood is being cross marched.
30. Cross match (Rapid)…
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Sources of errors in cross-matching
Rouleaux
Auto agglutinins
Infected donor cells
Anti- A1
Over centrifugation
Dirty glass wares etc..
31. Review Questions
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1. What is cross-matching?
2. What is the purpose of cross-matching?
3. List the types of cross-match with their
constituents
4. List the stages of cross-match and their
respective importance in antibody detection.
