ABO Mismatched transfusion?

[Mau Feitio]

A patient was admitted to our hospital with GI bleeding and Hb=4,4.

The forward blood group was determined with cards from Ortho Biovue system. And was positive with anti-A and anti-B. The reverse grouping wasn´t done. The crossmatch was performed in antiglobulin phase. 4 AB units compatible of packed red blood cells were sent. One week later the patient was admitted again and 2 units were requested. This time both units were incompatible and no unexpected antibodies were found. It was then repeated both forward and reverse grouping and a discrepancy was detected (forward: AB; reverse: A). Can anyone explain why the patient had no reaction to the blood transfused?

[Yanxia]

The previous transfusion is safe maybe because the plasma is diluted with fluid so the antibody is not so strong. the compatible crossmatch is the proven, and this time the crossmatch is incompatible.

Edited May 10, 2011 by shily

[Mau Feitio]

Something is missing in this case. The patient received another AB transfusion 2 days later and crossmatch ok. One week later we prepared two units to the OR and one unit was incompatible and another was compatible. By that time he wasn´t transfused. The genotype of the patient is O1A1

Edited May 10, 2011 by Mau Feitio

[Malcolm Needs ☆]

Are you absolutely certain that the patient's plasma was not reacting with another antigen expressed on the reverse grouping A1 cells, such as M?

[John Eggington]

Was/is the patient's DAT positive? Why do you think they, originally, (forward) grouped as AB?

[Mabel Adams]

If the patient later typed as A she would not have reacted with the A1 cells but rather the B cells. Still the M question is valid. Our reverse cells are pools so usually anti-M reacts with both the A1 & B cells since the pools almost always contain M+ cells. How strong were the original & subsequent typing reactions?

[Malcolm Needs ☆]

If the patient later typed as A she would not have reacted with the A1 cells but rather the B cells.

Good point Mabel!

I'll have to read up on the ABO Blood Group System a bit more!!!!!!!!!!!!!!!!!

:giggle::giggle::haha::haha:

[galvania]

Okay - there are some important lessons to be learned from this case:

1. ALWAYS do a reverse group as well as a forward group

2. Always put up a reagent control in parallel.

Yeaars ago there was a case of an elderly man being grouped as AB pos (the reverse group was done, but misread); he died of a transfusion reaction. He was actually group A and the false positive result with the anti-B was due to the aquired B phenomenon. This could possibly be a case of aquired B too, as the patient has a GI bleed. However, I would be suprised if the Ortho cards picked up aquired B.

Again, if this patient really is an A, then the false positive result with the anti-B could be due to poor pipetting technique with carry-over from the anti-A well

So why no transfusion reaction initially IF the patient really is a group A?

Possibly the patient's antibody was extremely weak or diluted out if he had received lots of fluids IV because of the bleed; and the transfused blood didn't stay in him for very long????

You state that the patient is an A1O1. Have you done a genotype on this patient? If so, why? He hasn't had a stem cell transplant perhaps?????

[Mohandoss Murugesan]

can it be A2B with Anti A1??

Edited May 19, 2011 by Mohandoss Murugesan

[BankerGirl]

I, too, wonder why no reverse typing was done on the original specimen since it is incorporated into the cards. As I read the AABB standards, it is required. Also, how did the control react. My next question is this: if he typed as an A on the second specimen and had incompatible crossmatches with AB units, why did you crossmatch and transfuse more AB rcs the third time. Maybe I am reading the posts incorrectly. Do you have any patient history or reaction strengths to report?

[Mohandoss Murugesan]

i m wrong....