Rh Discrepancy in an Infant

[BankerGirl]

We have a 7 month old baby boy that was originally typed by two different techs as O Negative (he was 3 months old at the time). He came to us from another facility, and was multiply transfused with platelets and RC. We typed him using both gel and tube. He is now typing as O Positive by both methods. We have tested two different specimens and have not changed any of our reagents. He was born prematurely and is Hispanic. All specimens were drawn by lab personnel. His first Rh positive specimen was 2+ positive at 6 1/2 months and is 4+ positive today, 2 weeks later. Does anyone have any ideas? Could the multiple transfusions have masked the D enough to be undetectable on the first specimen? Thanks in advance.:(

[adiescast]

If he was transfused with Rh negative blood multiple times, his Rh positive blood could easily have been masked. Sometimes the multiply transfused infants actually slow blood production of their own. We had one infant that was transfused in utero and after birth that we still couldn't get a decent type on a year after birth.

[bmalon3]

I agree. Since the child had multiple transfusions of 0 neg blood, the "real" blood type is being masked. We get transport babies all the time, and we have to confirm the original cord blood type with the facility who sent the child.

[L106]

BankerGirl -

Did your techs do a "Weak D" test when they first encountered this child? If you didn't (and it seems like the majority of Transfusion Services no longer routinely do the Weak D test), it is even more likely that the child is actually Rh Pos and was transfused with a large amount of O Neg donor red cells.

[BankerGirl]

I do not believe that they did. Had he been a newborn, the computer would have prompted them to perform a weak D, but there is no record of them performing it. Maybe I need to work on that for young babies as well as neonates. Thanks.

[rravkin@aol.com]

BankerGirl -

Did your techs do a "Weak D" test when they first encountered this child? If you didn't (and it seems like the majority of Transfusion Services no longer routinely do the Weak D test), it is even more likely that the child is actually Rh Pos and was transfused with a large amount of O Neg donor red cells.

Hey Donna,

This thread seems to bring us back to another thread where the question was asked "how do we change an initial positive ABSC to negative?" Here, of course is the Rh. In practice since there is a discrepancy in the Rh result that will need to be corrected should we not just continue to give Rh-neg products? Also, I am noticing that I have not seen any posts from Malcolm on these past threads; is he on vacation? :)

[Malcolm Needs ☆]

Hey Donna,

This thread seems to bring us back to another thread where the question was asked "how do we change an initial positive ABSC to negative?" Here, of course is the Rh. In practice since there is a discrepancy in the Rh result that will need to be corrected should we not just continue to give Rh-neg products? Also, I am noticing that I have not seen any posts from Malcolm on these past threads; is he on vacation? :)

No, I'm not on vacation - but my lap top was - it blew up (see the thread about Lap top disaster)!

I am quite certain that this phenomenon was due to D Negative blood being transfused to the foetus/neonate. This, in sufficient volume, will cause the chemoreceptors to "think" that there is sufficient oxygen carrying capacity, and they will "shut down" erythropoesis. The foetus/baby will, therefore, not produce any of his or her own D Positive red cells for quite some time and, on occasion, this "shut down" will take sufficiently long to start up again that the baby may require further transfusions to bring up the oxygen carrying capacity to sufficiency. I have seen this situation particularly in cases of anaemia due to parvovirus.

I would certainly perform a test for Weak D, and look for mixed-field reactions. If these were present, I would be happy to transfused D Positive blood (whereelse would the D Positive red cells have come frombut from the baby's own erythropoetic tissue?), BUT I would also like to know the C and E status.

I would be looking to get the baby genotyped by molecular methods, but I fully realise that this is not an option for everyone.

:):)

[John C. Staley]

No, I'm not on vacation - but my lap top was - it blew up (see the thread about Lap top disaster)!

I would be looking to get the baby genotyped by molecular methods, but I fully realise that this is not an option for everyone.

:):)

Malcolm, why would you want to go to all the trouble and EXPENSE to have this baby "genotyped by molecular methods" at this stage of the process?

The true joy of reference work must be in the challenge of Unicorn hunting.

:boogie:

[Malcolm Needs ☆]

Malcolm, why would you want to go to all the trouble and EXPENSE to have this baby "genotyped by molecular methods" at this stage of the process?

The true joy of reference work must be in the challenge of Unicorn hunting.

:boogie:

Actually John, thinking about it, that is an excellent point. I have gone way over the top. Thanks for bringing me back down to Earth!

:redface::redface::D:D:D

[David Saikin]

Obvioulsy (I think) the child is Rh+ ( he is typing 4+ now). Based on his history of multiple transfusions prior to being seen by your institution, I think you have to go with what you are seeing now. We had a GI bleeder transported to us from another facility, He was B+ /rec'd 16 B+ rbcs and 20 group B plasmas. 4 days later we had to do some crossmatches. The new specimen was still B+ BUT mixed field and those unagglutinated cells were O Negs. My point being that when you receive a transported patient who has been multiply transfused at another facility, you are at the mercy of the folks that did the orginal work. I wouldn't beat my head against the wall trying to figure this out. A good strong 4+ reaction is obvously valid especially considering the history of your transport.

[BankerGirl]

Well I did change the little boy's blood type to O positive and that is what we are transfusing him with now. Our supplier is much happier with O pos than they were with O neg, as they have been very short on O negs the last week. It just always causes us to shudder when we see a patient's blood type change, no matter what the reason.

Thanks to all who responded...even you Malcolm! Happy zebra hunting!