Crossmatching:
A hematological lab test, used to test for compatibility between donor and recipient blood before any transfusion process. So the purpose of cross matching is to prevent the transfusion of incompatible cells and to minimize, as much as possible, the risk of hemolytic transfusion reactions.
Types of crossmatch:
1) Majorcross match:
• To detect the presence of Ab's in the pt's serum against the donor’s Ag's.
• Use pt serum and donor cells.
2) Minor crossmatch:
• To detect the presence of Ab's in the donor's serum against the pt's Ag's.
• Use donor serum and pt cells.


1) Major Crossmatch:
It directly detects ABO and Rh incompatibility in addition to other clinically significant unexpected antibodies, that the recipient’s serum might have against the donor’s red cell Ag’s.
The first step is the “immediate spin” cross match, which will detect ABO/ Rh and unexpected cold agglutinins; if compatible the test tube is incubated at 37C to detect clinically significant agglutinins. And again if compatible, the final step would be the “Anti-Human Globulin” phase
Procedure:
Phase A: immediate spin crossmatching:
1. Identify pt’s sample.
2. Determine pt’s ABO and Rh type.
3. Select ABO identical blood unit for crossmatching.
4. Prepare a 5% suspension of the donor unit.
5. Determine ABO and Rh type of the donor unit.
6. Label a tube with the pt’s name.
7. Add 2 drops of the pt’s serum to the tube.
8. Add 1 drop of the donor’s cells (from the suspension) to the tube.
9. Mix and centrifuge for 30 sec at 2000 rpm.
10. Read the result:
Agglutination OR hemolysis: the unit is incompatible!
Causes: - Major ABO incompatibility.
- Presence of cold alloantibodies.
No agglutination OR hemolysis: continue with phase B.
Phase B: incubation phase:
11. To the same tube add 2 drops of Bovine Serum Albumin (BSA) or LISS (Low ionic Strength Solution) “now the function of these solutions is to increase the attraction between the Ab’s and the Ag’s”. (if present, the Ab’s will bind to the Ag’s but the reaction will not form a lattice, i.e. the RBC’s will be sensitized but no agglutination will appear).
12. Incubate at 37C for 15-30 min.
Phase C: Coomb’s phase:
13. Wash the cells 4 times (to get rid of any unbound Ab’s).
14. Add 2 drops of AHG (now at this step the sensitized RBC’s will form the lattice structure and agglutination will appear).
15. Mix and immediately centrifuge for 30 sec at 2000rpm.
16. Check for agglutination:
Agglutination occurs: the unit is incompatible.
No agglutination: continue with step 17
17. confirm your result and the validity of the test by using IgG coated Rbc’s
Result interpretation:
- if all tubes have remained –ve throughout the cross match procedure, then the antibody screening is –ve and the unit is interpreted as “ compatible”.
- If agglutination or hemolysis appears at any stage the unit is interpreted as “incompatible”, and the nature of immunoglobulins the pt has should be identified.

2) Minor crossmatch:
As far as I know this one is not used for compatibility testing, because it will only give an indication about the ABO Ab’s but not the Rh Ab (or as we call it the anti-D).
Now, regardless of the procedure, let’s consider you want to test the compatibility for a recipient and a donor (regardless of the blood type) via minor cross matching.
You would have to take the donors serum and react it with the recipients cells. If any agglutination or hemolysis occurs it would be due to ABO incompatibility but not due to Rh incompatibility!! Because the anti-D is an occasionally occurring Ab i.e. it only occurs when exposed to the Rh Ag and does not remain in the blood forever.
So you can’t actually tell if the recipient and donor are Rh compatible or not via minor crossmatching.

Now regarding the techniques, some of which I know are the tube method and the gel card method. In the attached link both methods are mentioned, hopefully they’re useful for u.
Good luck.

http://libserv5.tut.ac.za:7780/pls/e...7/ReynekeT.pdf

mmmmmmmmmmmmmmmmmh :more67::more67::more67:
lesch ma 3am yirda yi6la3 from the left to the right????:sm196::sm196::sm196:
inschalla ikun wade7.

مشكورة دكتوره على هدا الشرح الوافي والمتكامل ويعطيك العافيه

الله يعافيك اخي hussen99

الله يعطيييييييييييك العافية:sm188:

الله يعافيك اختي هدووووووووووولة:sm171:

مشكوووووووووووووووووووووووووووووووووووووورة

ويعطيك ألف عافية

thanks alot Dr.Rascha B.S
:sm170:

الله يعافيك اخي علووش
& u're welcome mr_boss

:sm188: Thanx Doctor :sm188:

you're welcome bacteria
:sm171: