CROSS MATCHING

 

CROSS MATCHING

Cross matching also known as compatibility testing.

It is the most important test before a blood transfusion.

Cross matching is a procedure performed prior to a blood transfusion to determine whether donor blood is compatible (or incompatible) with recipient blood.

WHY CROSS MATCH REQUIRE.

If the blood group are matched there are 90% chances of their compatibility. However there are some cases in which blood are blood group are match but cross-matching is incompatible.

The donor may have unexpected antibodies in his serum.

The patient may have unexpected antibodies in his serum.

Mistake in blood grouping.

PURPOSE AND IMPORTANCE

• It detects errors in ABO grouping.
• It prevent transfusion reaction.
• It ensures maximum benefits for the recipient of compatible blood.

HOW TO PERFORMED IT.

This procedure is performed in two parts.

Major cross-match: the donor cells are mixed with the patient serum. This brings reaction of donors red cells with patients serum or plasma to detect antibodies that could destroy donors red cells.

Minor cross match : the patient cell are mixed with the donors serum/plasma. This brings reaction of patients red cells with donor serum or plasma to detect antibodies that would destroy patient red cells.

REQUIREMENT

• Small test tubes.
• Pasteur pipette.
• Normal saline.
• Centrifuge.
• Patient sample.( Blood cell or serum/ plasma)
• Donor sample. ( Blood cell or serum / plasma)

PROCEDURE FOR MAJOR CROSS MATCH

1. Prepare donor and recipient’s blood sample: Donor’s red cells and recipient’s serum/plasma.
2. Prepare 3-5% saline cell suspension of red cells.
3. Label a test tube.
4. Add two drops of recipient’s serum and one drop of donor cell suspension.
5. Mix and incubate the tubes at 37 degree Celsius for about 60 minutes.
6. Decant the serum completely and wash the cells three times in saline.
7. Add two drops of Anti-human Globulin (AHG) and mix. Allow to stand at room temperature for 5 minutes.
8. Centrifuge at 1500 rpm for 1 minute.
9. Observe macroscopically and microscopically for agglutination.
10. If macroscopic agglutination is not observed, transfer a small amount onto a glass slide and examine for microscopic agglutination. Rouleaux is not an indication of incompatibility.

PROCEDURE OF MINOR CROSS MATCH.

1. Prepare donor and recipient’s blood sample: Recipient’s red cells and donor’s serum/plasma.
2. Label a test tube.
3. Add two drops of donor’s serum and one drop of recipient’s cell suspension.
4. Mix and incubate the tubes at 37 degree Celsius for about 60 minutes.
5. Decant the serum completely and wash the cells three times in saline.
6. Add two drops of Anti-human Globulin (AHG) and mix. Allow to stand at room temperature for 5 minutes.
7. Centrifuge at 1500 rpm for 1 minute.
8. Observe macroscopically and microscopically for agglutination.
9. If macroscopic agglutination is not observed, transfer a small amount onto a glass slide and examine for microscopic agglutination. Rouleaux is not an indication of incompatibility.

INTERPRETATION

• If agglutination shows in major cross match should never be transfused.
• If agglutination shows in minor cross match should not be transfused. But in case of emergency it is possible to use blood.