Hello, 

I am new to the forum! There's a case study at the hospital I work at and there's one question everyone's having trouble with. Patient is A pos and the question is "why are there reactions at immediate spin reading that do not show up at the AHG reading?". My first thought would be a cold antibody, but that typically has a reaction at immediate spin with a weak reaction at AHG, correct? What do you all think? 

Thanks! 

possible anti A1?  

6 minutes ago, R1R2 said:

possible anti A1?  

I also considered this. The patient had two type and screens prior to the transfusion that both resulted as A pos and negative antibody screen. The post transfusion type and screen resulted as anti-A (4+), anti-B (neg), anti-D (4+), A1 (neg), B (3+), and a positive antibody screen. If an anti-A1 were present, wouldn't there be an ABO discrepancy? 

21 minutes ago, Red0Rose said:

Hello, 

I am new to the forum! There's a case study at the hospital I work at and there's one question everyone's having trouble with. Patient is A pos and the question is "why are there reactions at immediate spin reading that do not show up at the AHG reading?". My first thought would be a cold antibody, but that typically has a reaction at immediate spin with a weak reaction at AHG, correct? What do you all think? 

Thanks! 

First of all, welcome to this wonderful site.

It depends upon how you perform your antiglobulin tests, and also what kind of AHG you use.  Please could you let us know?

1 hour ago, Red0Rose said:

I also considered this. The patient had two type and screens prior to the transfusion that both resulted as A pos and negative antibody screen. The post transfusion type and screen resulted as anti-A (4+), anti-B (neg), anti-D (4+), A1 (neg), B (3+), and a positive antibody screen. If an anti-A1 were present, wouldn't there be an ABO discrepancy? 

I assumed your screen was negative.  What was the panel results of the positive antibody screen?  

If the screen is negative by IS, it rules out the presence of a generic "cold". Are you only seeing this phenomenon during an IS crossmatch ? Are you only crossmatching group A units ? Does the same "incompatibility" happen if you crossmatch group O units ?

Typically antibodies detected prior to an antiglobulin phase are IgM. These do not necessarily "carry through" to the antiglobulin phase, especially if they have limited thermal amplitude.

Since IS is at room temp, couldn't it just be an odd non-specific anti-M antibody?  Some antigen present on the reverse cell or cells but not on the screening cells?

Scott

47 minutes ago, SMILLER said:

Since IS is at room temp, couldn't it just be an odd non-specific anti-M antibody?  Some antigen present on the reverse cell or cells but not on the screening cells?

Scott

Anything is possible, but the screening cells are designed with the intent to detect all (common) antibodies, including the antibodies traditionally considered "colds" - MN, Le^a/b, P₁, etc. It is remotely possible that the frequencies/incidences of an antigen have come together perfectly to yield these results, but you'd have to be very lucky or unlucky, depending upon your point of view.

29 minutes ago, exlimey said:

Anything is possible, but the screening cells are designed with the intent to detect all (common) antibodies, including the antibodies traditionally considered "colds" - MN, Le^a/b, P₁, etc. It is remotely possible that the frequencies/incidences of an antigen have come together perfectly to yield these results, but you'd have to be very lucky or unlucky, depending upon your point of view.

This was exactly why I wanted to know by what technique the IAT was performed, and what type of AHG was used.

On 5/3/2017 at 7:10 AM, Red0Rose said:

Hello, 

I am new to the forum! There's a case study at the hospital I work at and there's one question everyone's having trouble with. Patient is A pos and the question is "why are there reactions at immediate spin reading that do not show up at the AHG reading?". My first thought would be a cold antibody, but that typically has a reaction at immediate spin with a weak reaction at AHG, correct? What do you all think? 

Thanks! 

Ok, I may be missing something here but my first question is, what testing are you seeing this in?  Is this happening in the crossmatch or the antibody screen or both? It may not make a difference but it is important information. 

21 hours ago, exlimey said:

Anything is possible, but the screening cells are designed with the intent to detect all (common) antibodies, including the antibodies traditionally considered "colds" - MN, Le^a/b, P₁, etc. It is remotely possible that the frequencies/incidences of an antigen have come together perfectly to yield these results, but you'd have to be very lucky or unlucky, depending upon your point of view.

We have seen this happen with a few patients, though it is indeed very unusual.  We figure that a patient is developing a (likely transient) IgM antibody to one of those unusual antigens mentioned above, that just happens to be present on the reverse reagent RBCs.  Using another lot number has always resolved the issue.  In cases where it does not, we are stuck with an indeterminate ABO typing.

Scott