Does this blood bank "critical thinking" question makes sense to anyone?

[yan xia 199]

There are a lot of brilliant explanations, I learned so much from here.

 My guess about the pos DAT is that if the DAT(IgM) is positive, then it may cause false positive result in the D testing. This is why when we test a sample which is AB Dpos, we will run a neg control for the forward typing.

 

 

[exlimey 386]

On 2/19/2021 at 4:09 PM, diplomatic_scarf said:

 

I disagree. Most gel cards and Anti-D reagents won't detect DVI for patients. Fortunately I can find numerous suitable quotes, because it's true. 

 

 

 

https://labs-inc.org/pdf/361_3.pdf

 

Apologies. I was discussing reagents used in tubes, not gel cards.

[Bijoux71 2]

In scenarios like this, questions and possibilities that first come to mind are the following, not in any specific order:

 

1.) The DAT of the donor unit is extremely relevant.  Yes, DATs are not routinely run on all donors however, when IRL testing discovers a discrepant IAT antigen type, Rh or other, a positive DAT is often the culprit.  If the discrepant type is at immed spin or direct agglutination, several possibilities come to mind, such as a bacterial contaminated donor unit which may cause spontaneous agglutination, or a medicine that donor takes and is not screened for or donor doesn't give an accurate reply to pre-donation questions, or a donor with a cold agglutinin.

2.) Some previous posts have stated that most current Anti-D reagents will not detect DVI.  I feel like that statement is confusing and should be worded to say "most Anti-D reagents will not detect type DVI by direct agglutination, but are able to detect DVI at IAT. 

 

[Malcolm Needs ★ 4,923]

21 minutes ago, Bijoux71 said:

2.) Some previous posts have stated that most current Anti-D reagents will not detect DVI.  I feel like that statement is confusing and should be worded to say "most Anti-D reagents will not detect type DVI by direct agglutination, but are able to detect DVI at IAT. 

 

I think you would also need to re-word your comment slightly, as your comment, as written, is not valid in all countries.

Within the BSH Guidelines for pre-transfusion compatibility procedures in blood transfusion laboratories (Milkins C, Berryman J, Cantwell C, Elliott C, Haggas R, Jones J, Rowley M, WIlliams M, Win N.  Transfusion Medicine 2013; 23: 3-35) states, in paragraph 4.3.2 D typing, "i  Where secure automation is used, D typing may be undertaken using a single IgM monoclonal anti-D reagent, which should not detect DVI.  In the absence of secure automation, each sample should be tested in duplicate, either with the same reagent or with two different IgM monoclonal anti-D reagents; this is to reduce the risk of cross-contamination and the potential for procedural error where manual testing is undertaken." (my bold font).  It will be seen that the Guidelines state "which should not detect DVI", rather than "which should not detect DVI by direct agglutination", and, having served for some time on the Transfusion Task Force of the British Society for Haematology, I can assure you (and others) that each and every phrase and sentence in any of these Guidelines is discussed to the nth degree to ensure that what is printed is what is meant.

The Guideline goes on to give much more detail in terms of what testing or reagents should be used in different circumstances.

[RichU 7]

We use BioRad gelcards. There are different ABD-Confirmation cards for Donors and Patients. The Donor one detects DVI, the patient one does not.

The D status of all donors found negative by the ABD conf card are confirmed using a monoclonal anti-D by IAT.

Is re-grouping of units, sent from the blood bank, at the hospital a thing?

Sorry for the late post

Edited April 7 by RichU
Forgot to add question.

[Malcolm Needs ★ 4,923]

28 minutes ago, RichU said:

We use BioRad gelcards. There are different ABD-Confirmation cards for Donors and Patients. The Donor one detects DVI, the patient one does not.

The D status of all donors found negative by the ABD conf card are confirmed using a monoclonal anti-D by IAT.

Is re-grouping of units, sent from the blood bank, at the hospital a thing?

Sorry for the late post

Not in the UK.

[AMcCord 1,296]

22 hours ago, RichU said:

We use BioRad gelcards. There are different ABD-Confirmation cards for Donors and Patients. The Donor one detects DVI, the patient one does not.

The D status of all donors found negative by the ABD conf card are confirmed using a monoclonal anti-D by IAT.

Is re-grouping of units, sent from the blood bank, at the hospital a thing?

Sorry for the late post

In the U.S. we are required to confirm donor types at the hospital.

[Joanne P. Scannell 231]

I'm chuckling reading all of this because it's like the question, 'If the parents are both Group O, can they produce a Group A baby?'

Ask a student, they'll say 'No way!'.

Ask a BB fanatic, they'll say, 'Sure it could happen ... and here's how ...'

And in this forum, there is never a simple answer!

[diplomatic_scarf 14]

36 minutes ago, Joanne P. Scannell said:

I'm chuckling reading all of this because it's like the question, 'If the parents are both Group O, can they produce a Group A baby?'

Ask a student, they'll say 'No way!'.

Ask a BB fanatic, they'll say, 'Sure it could happen ... and here's how ...'

And in this forum, there is never a simple answer!

 

 

"Sure it could happen ,,, and here's how... one of the parents perhaps has the Bombay phenotype" 

[galvania 811]

or mum is a surrogate

or baby is the result of an ivf with external donors

 

[mrmic 57]

Although the question and answer are troublesome the following statement in the "question" cannot be ignored. (Investigation of the label issued at the blood bank verified the unit's correct labeling.) 

Since the blood center typing was investigated and verified the label was correct, then, the typing at the transfusion service should be suspected.  The information put forth by Malcolm and Johnv seem likely if one investigated the transfusion service typing.

Donor centers are quite aware of regulations regarding donor testing and labeling.  So not all suspected "mislabeled" units should not be automatically the donor center's error.  They employ SBB technologists too.  Their investigation should be discounted.

Based on what the author was expecting to be the "only" correct answer, certainly reflects the problem of the way the question was written.

It's not always easy writing "critical thinking" Immunohematology questions.  So it might be an exception for the author of the question and not the norm.   However, it did succeed at providing some stimulated conversation and valuable references for all!