The Compatibility can be determined by matching the different blood group systems, such as ABO and Rh system, and/or by directly testing for the presence of antibodies against a sample of donor tissues or blood. The main purpose of this test is to distinguish the appearance of antibodies in the recipient against the red blood cells of the donor. These antibodies can be found on the surface of red blood cells of the donor after transfusion. 

1. PRESENTEDBY
D. JASMINE PRIYA
ASSISTANT PROFESSOR
DEP OF MLT
SATHYABAMA INSTITUTE OF SCIENCE AND TECHNOLOGY
CHENNAI – 19
COMPATABILITY
TESTING

2. COMPATABILITY TESTING
Cross Match is a laboratory test, performed prior to a blood transfusion
to determine whether donor blood is compatible (or incompatible) with
recipient blood.
The Compatibility can be determined by matching the different blood
group systems, such as ABO and Rh system, and/or by directly testing for
the presence of antibodies against a sample of donor tissues or blood.
The main purpose of this test is to distinguish the appearance of
antibodies in the recipient against the red blood cells of the donor. These
antibodies can be found on the surface of red blood cells of the donor after
transfusion.

3. An incompatible transfusion can lead to severe hemolytic anemia and
even death.
The Cross Match test does not perform in dogs and horses, because in
them the naturally occurring antibody against important hemolytic red
blood cell antigens are absent.
Hence, these animals need sensitization to the red cell antigen, before
a hemolytic reaction will occur.
After completion of blood transfusion to a dog or horse, a crossmatch
should be performed prior to any subsequent transfusions to detect
antibodies that may have been produced against a different red blood
cell antigen.

4. Principle of Cross Matching
Cross-matching is based on the serological detection of any clinically
significant abnormal/unexpected antibodies in the blood of either the
donor or the receiver. There are two varieties of cross-matching:
1. Major Cross Match: It entails comparing the donor’s red cells with the
recipient’s serum to evaluate the presence of any antibodies that may
cause hemolysis or agglutination of the donor’s red cells. This is more
crucial than minor cross-matching.
2. Minor Cross Match: It entails analyzing donor plasma with recipient
red cells to evaluate the presence of any antibodies that may cause
hemolysis or agglutination.

5. Type Donor’s Recipient’s
Major Cross Match Red Cells Serum/Plasma
Minor Cross Match Serum/Plasma Red Cells

6. Major Cross Match – PROCEDURE
1. Prepare blood samples from both the donor and the recipient, including the
donor’s red cells and the recipient’s serum/plasma.
2. Prepare a 3-5% red cell suspension in saline.
3. Label a test tube.
4. Add two drops of the donor’s serum and one drop of the recipient’s serum.
5. Mix and incubate the tubes for 60 minutes at 37 degrees Celsius.
6. Remove all of the serum and wash the cells three times in saline.
7. Mix with two drops of Anti-human Globulin (AHG). Allow to stand for 5
minutes at room temperature.
8. Centrifuge at 1500 rpm for 1 minute.
9. Using both macro- and microscopy, search for agglutination.
10.If no macroscopic agglutination is noticed, a little amount should be
transferred to a glass slide and examined for microscopic agglutination.
Rouleaux does not signify incompatibility.

8. Minor Cross Match – PROCEDURE
1. Prepare blood samples from the donor and recipient: the recipient’s red cells
and the donor’s serum/plasma.
2. Label a test tube.
3. Add two drops of serum from the donor and one drop of cell suspension
from the recipient.
4. Mix and incubate the tubes for 60 minutes at 37 degrees Celsius.
5. Remove all of the serum and wash the cells three times in saline.
6. Mix with two drops of Anti-human Globulin (AHG). Allow to stand for 5
minutes at room temperature.
7. Centrifuge at 1500 rpm for 1 minute.
8. Using both macro- and microscopy, search for agglutination.
9. If no macroscopic agglutination is noticed, a little amount should be
transferred to a glass slide and examined for microscopic agglutination.
Rouleaux does not signify incompatibility.

10. Result of Cross Matching
Both major and minor cross-matches should reveal no agglutination
between compatible donor and receiver blood.
Blood that is incompatible in a major cross-match should never be
transfused, as the recipient’s huge plasma volume containing
antibodies can quickly destroy the donor’s red cells.
Minor incompatibility is less significant since the antibodies in the
donor’s serum are diluted in the recipient’s plasma, rendering them
useless.

11. APPLICATION OF CROSS MATCH TEST
1. This test is used during a blood transfusion.
2. Cross Match test is used if anyone having a certain medical problem
that could cause significant blood loss, such as a cesarean section, a
renal biopsy, or a cholecystectomy.
3. Used for sickle cell disease or thalassemia.
4. Used to check the effects of chemotherapy.
5. Used for detection of a bleeding disorder, for example, hemophilia.
6. During pregnancy, this test is used to find out if the patient is Rh-
negative or positive.
7. This test is performed during organ transplant, bone marrow
transplant, or tissue transplant.

12. Why to Get Cross matching?
Cross matching is a laboratory test that is used to determine
compatibility between a potential blood donor and a recipient before a
blood transfusion is given. There are several reasons why cross matching is
important:
1. To reduce the risk of transfusion reactions: Cross matching helps to
reduce the risk of transfusion reactions, which are adverse reactions that
can occur when the donor’s blood and the recipient’s blood are
incompatible. Transfusion reactions can range from mild to severe and can
include symptoms such as fever, chills, shortness of breath, and hives.
2. To ensure the safety of the transfusion: Cross matching helps to ensure
the safety of the transfusion by identifying any potential incompatibilities
between the donor’s blood and the recipient’s blood. This helps to reduce
the risk of complications that may occur as a result of the transfusion.

13. 3. To match the blood type of the donor and recipient: Cross matching
helps to match the blood type of the donor and recipient to avoid
complications such as hemolysis (the breakdown of red blood cells). It is
important to match the blood type of the donor and recipient to ensure
that the transfusion is successful and does not cause any adverse reactions.
4. To match the Rh blood group of the donor and recipient: Cross matching
also helps to match the Rh blood group of the donor and recipient. The Rh
blood group system consists of two blood types: Rh positive and Rh
negative. It is important to match the Rh blood type of the donor and
recipient to avoid complications such as hemolysis (the breakdown of red
blood cells).
Overall, cross matching is an important step in the process of transfusing
blood to ensure the safety of the recipient and to reduce the risk of
transfusion reactions and other complications that may occur as a result of
the transfusion.

14. Why do I need this test?
It is not possible for me to determine why you specifically may need a blood
cross matching test without more information. Blood cross matching is a
laboratory test that is used to determine compatibility between a potential
blood donor and a recipient before a blood transfusion is given. There are
several reasons why a person may need to have a blood cross matching test,
including:
1. To prepare for a blood transfusion: If you are going to receive a blood
transfusion, your healthcare provider may order a blood cross matching test to
ensure that the donor’s blood is compatible with your blood. This helps to
reduce the risk of transfusion reactions and other complications that may
occur as a result of the transfusion.

15. 2. To check for bleeding disorders: If you have a bleeding disorder, your
healthcare provider may order a blood cross matching test to determine
if you have any antibodies that may react with the donor’s blood. If you
have antibodies that react with the donor’s blood, it could cause a
transfusion reaction.
3. To prepare for surgery: If you are going to have surgery, your
healthcare provider may order a blood cross matching test to ensure
that you have enough red blood cells and to check for any potential
incompatibilities between your blood and the donor’s blood.
4. To diagnose a blood disorder: If you are experiencing symptoms that
may be related to a blood disorder, your healthcare provider may order a
blood cross matching test to help diagnose the condition.

16. What happens if crossmatch is positive?
If a blood crossmatch test is positive, it indicates that there is an
incompatibility between a recipient’s blood and a donated blood product.
This means that the transfusion or transplant should not proceed unless
additional testing or precautions are taken to ensure the safety and success
of the procedure.
A positive crossmatch does not necessarily mean that the transfusion or
transplant cannot proceed, but it does indicate that additional testing or
precautions may be necessary to ensure the safety and success of the
procedure. Some possible options in the event of a positive crossmatch may
include:

17. 1. Performing additional cross matching tests to determine the
specific cause of the incompatibility
2. Using a different blood product that is compatible with the
recipient’s blood
3. Pre treating the recipient’s blood with medications to remove or
neutralize any antibodies that may cause a reaction with the
donated blood product
4. Using a blood product from a universal donor, such as type O
negative red blood cells