For me a somewhat unusual example, I would appreciate your opinions on it.
                  4C           37C           Prewarmed
Screen        H             1+             neg
Ak panel    H             1+             neg
Auto           H            1+              neg
With routine screen on gelcard (anti-IgG) at 37C all cells became 1+, NaCl tube test at 4C gave lysis with all cells, prewarmed on gelcard (anti-IgG) neg on all cells.
                               Room temp         37C
Forward    A           neg    
                  B           4+    
                 Ctr         neg    
Reverse    A1          2+                      neg
                  B           4+                      3+
Extra reaction in reverse grouping in room temperature    
DAT    IgG    1+
          C3d    2+
Sample stored at 4C overnight gave extensive lysis and an unusable sample 

So a cold antibody that activates compliment, our laboratory rarely see lysis like this.
How do you guys routinely investigate this? Do you do anything more? Cold titer? Recommending a blood warmer?
 

I have an idea of what I think it might be, but I would hesitate to say without a bit more information concerning the condition and underlying pathology of the patient.

How old is the patient?  Have they recently had something like an atypical pneumonia?

I think, without knowing the answer to the above questions, that the specificity of the antibody MAY be between "anti-O" and "anti-Q".

I would suggest performing an indirect DL-test.

I may well be wrong, OF COURSE, but the attached may help.

Paroxysmal Cold Haemoglobinuria (PCH).pptx

You are like an encyclopedia 

Should of course have included some information about the patient. 67 year old woman with anemia. Suspected AIHA, but no established diagnosis. The patient has been moved to a larger regional hospital, so it is not certain we will get the final diagnosis.

So "anti-O" and "anti-Q"? I opened my trusty antigen factsbook, but nothing…   do you mind telling me more?

We only perform DL-tests at the request of the department/patient responsible doctor, as we do not perform them in house. Did you perform DL-test routinely?

Edited January 27, 20232 yr by Walter Isenheim

I was joking about the specificity being between "anti-O" and "anti-Q", in that anti-P, the specificity almost always involved in a case of PCH is a "cold-reacting" IgG anti-P that "fixes" complement (and P is between "O" and "Q" in the Western alphabet).  A pretty poor attempt at a joke, I fully admit!

While I am not saying definitely that it is a case of PCH, the fact that the patient has a suspected AIHA, that the auto-antibody appears to be "cold-reacting", that it is IgG and that it also involves activated complement, strongly suggests that this may be the line to go down as an investigation.

We didn't perform a DL test routinely by any manner of means (despite being a London based Red Cell Immunohaematology Laboratory).  It was always discussed between our own Consultant (or, at night, weekends or Bank Holidays) by the on-call Consultant, but all of the staff knew how to perform the test, even if they were a lone worker.  We always used to dread being asked to perform such a test as a lone worker, as it took so long to do!

Man you got me good, started searching for anti-O and anti-Q and thought that I missed something big  It's cool, no hard feelings! 

Anti-P sounds much more familiar. 

That's why we don't do DL test ourselves, we don't have time for it.

Sounds like a case I would have had at the IRL

@Malcolm Needs......YAY!  it always makes me feel a little "smarter" when my thoughts are consistent with your answers!!!  PCH was my first thought!

I know I'm old and been out of the world for a while but I have to ask, what is this DL you are referring to??  

The Donath-Landsteiner Test for the Donath-Landsteiner antibody (IgG auto-anti-P that binds complement) that causes PCH (see the PowerPoint I attached above).

2 hours ago, Malcolm Needs said:

The Donath-Landsteiner Test for the Donath-Landsteiner antibody (IgG auto-anti-P that binds complement) that causes PCH (see the PowerPoint I attached above).

I hate to admit it but I don't remember ever hearing about that test in my 35* years in Blood Banking!  I guess you are never too old to learn something new, but remembering it is another story.  Thanks Malcolm.

Thanks Walter for sharing such an interesting case. PCH is definitely something I would investigate in this case, although the hemolysis at 4C is rather atypical in a case of a positive LD test. I would also check for drug induced hemolysis ( An eluate would be informative in this case). I couldn't understand why your NaCl tube test at 4C gave lysis as well... (this reminded me of a time when one of my coworkers were getting such weird reactions ....turns out she somehow was using DI water instead of blood bank saline!