Blood Cross Matching

[mayennaise]

My MIL is having a blood transfusion tomorrow and has to be at the hospital really early so that they can 'cross match' her blood in the lab before they commence the transfusion. As this is the second transfusion she's had in 4 months, surely her blood group details wouldn't have changes from the last time and they'd be in her hospital notes ! ? ! ?

[black_cat51]

although that's true, the consequesnces of getting the wrong blood are fatal, so it's best to check. BTW your blood group can change after a bone marrow transplant

[woofgang]

Its quite proper to take such care as a mis match can be fatal. Blood type changes slightly after every transfusion as well.

[michellebaker163]

The blood group does not change but you can develop antibodies in the blood. These can develop at anytime, so cross matching must be repeated - especially as had a previous transfusion, she may have acquired antibodies since. Hope this helps

[mayennaise]

Oh I see - trouble is, she's 80, lives an hour away from the hospital and has got to be there at 8am tomorrow morning. As she only has one speed (v slow!) she'll be getting up in the middle of the night to make sure she gets there on time.

[black_cat51]

i suppose it beats having to stay there till 9pm

[stewey]

When a "group and type" is done your blood is merely tested for your ABO group and your Rh type. A cross-match investigates all the other sub-groups (Kell, Duffy, etc, etc...) in order to make sure that the blood you receive is as compatible as possible.

[catscradle]

This is not just about the patient's own blood groups (these don't change as you say) - it's about what other blood groups they have reacted to (made antibodies to). They do not match donor and recipient for all the blood groups - only for ones the recipient has already reacted to (has antibodies to). The transfusion she had four months ago may have stimulated more reactions (antibodies), and so now she would have to be matched for those blood groups too. The more transfusions a person has, the more likely they are to have made antibodies, and cross-matching becomes more difficult.

[pixie373]

It does sound likely. I thought the same when they wanted to get my blood group each time i was pregnant. But if that's what they want to do, i would just go along with it.

[mayennaise]

Ah - all now becomes clear....... Thanks all

[stewey]

An interesting aside is that some people carry a card with their group and type on it in case of "emergencies". The blood bank depts of hospitals ignore these and go ahead and do a regular cross-match. If it is a real emergency, you will be transfused with the so called universal donor blood (O negative), and this is not guaranteed to be without possible complications.

[LazyGun]

As others have already pointed out, the reasons for having a crossmatch performed every time prior to a transfusion is for 2 principal reasons; To ensure that the blood allocated from inventory is ABO compatible, since an ABO incompatibility can have serious, even fatal outcomes, and secondly to check for the appearance of any unexpected antibodies within the circulation that may have developed from exposure to foreign antigens in previous transfusions.

The development of such antibodies is not guaranteed, but if they are present, they can again cause potentially quite serious medical complications - not something you would want at any age, but especially when you are 80 odd :)

Steweys description of what happens during catastophic blood loss is quite true, but slightly out of date now in that, in situations of catastrophic blood loss the initial concern relates to getting fluid into the patient to maintain blood pressure and prevent the patient going into hypovolaemic shock. This gives time to group and cross-match blood for the patient.

I have been involved in situations though where the ongoing management of a patient with multiple injuries has meant the transfusion of over 100 units of blood after the initial treatment with IV fluids, and in those situations we do not bother with a cross match; We only ensure ABO group compatibility, and in extreme cases it is not unknown to switch to different ABO groups in an effort to keep up with the blood loss.

Thankfully though, we new developments in IV fluids, peri-operative blood salvage systems and advances in treatments, such situations have become very rare.