ABO discrepancy

[VA blood banker]

Recently, I typed a patient as A who had a history of O. I asked for a new sample and the new sample typed as A. I then suspected that the "O" sample had been incorrectly collected. I discussed this w/ my super who had another theory. She said that there are times that a patient can change ABO type. i.e. if the patient is septic, the bacteria can de-nature the antigens on the surface of the RBC causing the reactions that don't reflect the patients true ABO. I would think that if that were the case the back type would reflect the patient's "true" ABO. How septic does one have to be to affect the front type?

Any comments?

[galvania]

I think the chances of it being 2 different patients is much higher. Sepsis can have an effect in the following situation: A group A1 person can aquire a 'B antigen' , the so-called 'aquired B' in certain cases of sepsis where the bacteria digest part of the 'A' terminal sugar to 'create' a B antigen. The patient then looks like an AB; usually the B is weaker than normal; and the reverse group would remain that of a group A. The 'aquired B' antigen can be picked up if you use polyclonal (human) anti-B reagents and certain clones.

The other thing that can happen is that with certain tumours, (as far as I know, they have to be in the GI tract) the cancerous cells can produce so much soluble A and/or B antigen that this neutralises the anti-A and anti-B reagents, so the patient appears to be a group O.

Alternately, if you've changed reagents, maybe the patient has a strange mutation of the A antigen which is being picked up by your current reagent but not by your previous one.

Or, has the patient received a stem cell graft (group A) in the meanwhile?

I'm sure other people may be able to think of other possible scenarios.

However, as I said at the beginning, the most likely cause is error - either sampling error (wrong blood in tube) or reading error or transcription error or..........

However, as I said at the beginning

[Mabel Adams]

One problem that I once had like this was when admitting used a historical patient for a new patient with the same name. All the data (except blood type) matched between history and current, it just didn't match the actual patient that was in.

Also, I hear reports of uninsured patients borrowing someone's ID so they can use their medical insurance coverage.

Does your admissions office do photo ID checks and compare history carefully?

[GilTphoto]

We just had a case a few weeks ago. History was O pos, currently B pos. The previous record was from 2001.

When we went back to redraw the patient, the patient questioned why? The phlebotomist told her the blood type didn't compare with her record from 2001. The patient replied, she has never been in this hospital before, but did have her wallet stolen in 2001. The person who stole her wallet, used her identity to get surgery done.

[geekay]

Hi there,

The chances of an "acquired antigen" due to some intestinal problems like malignancy or sepsis, are theretically right. But I understand that the artificial antigens will not be picked up by the newer generation antisera which are monoclonal. The earlier versions of antisera, which were polyclonal, used to give "positivity" for both natural and "artificial antigens". But in this present, where majority use monoclonal antisera, such problems and complications are extremely rare.

The present problem of "A or O " could have been sorted by the Blood Bank by comparing the grouping results using a "parallel run" with monoclonal and polyclonal antisera. .....

In addition, where there is a discrepancy like this, any sensible Blood bank would like to go by the rule "PLAY SAFELY"...and use "O group " Blood for transfusion if necessity comes.

best wishes...

[Mabel Adams]

There is no "acquired A antigen", just B, so I'd guess that couldn't explain the case presented. Clerical/ID errors are quite a bit more common than acquired antigens. Probably bone marrow transplants are more common, but you can usually get that history by asking.

[RWOOD57]

I have seen this happen when patient is O and had a group A bone marrow transplant. If that is not the case, I would suspect error in first specimen.

[Yanxia]

Mabel, if my memory not cheat me there has acquired A antigen, it is a kind of T polyagglutination, been agglutinated more strongly in B serum.

[LAS]

My money is on a specimen mix-up either at time of collection or during testing.

[martha]

How old is the patient? Being a children hospital this very common for us. Multiple transfusion of O RBC to neonates can give you an ABO discrapency. When the patient's are transferred to us they type O (may time we do not see mixfield) after four month we request new sample and we start seeing their real type.`

Martha

[Liz0316]

I agree, the most likely explaination is an error in either collection or testing. Do, keep in mind, the error might have been on the first typing, so the new one could be correct. How long ago was the first type done? Monoclonal ABO reagents are much better (and more specific) than the older polyclonal. If you have the time, you could try a different manufacturer - could be a different clone; although there are only a couple of clones out there. Good luck.

[San]

how about a bone marrow transplant? I have seen that a couple of times.

OR.....ppl sharing insurance cards..that also has happened to us.

[rlmirand]

Consider fraud like Mabel suggested. It is not uncommon.