I am interested in how the following scenarios would be handled in your reference lab:

[scenario 1]

Test tube with PeG additive: negative panel at AHG.

Gel panel: 1+ to +w with all cells.

DAT and autocontrol are negative.

What additional testing, if any, would you perform?

[scenario 2]

Same as Scenario 1, except:

Autocontrol and DAT are positive.

What additional testing, if any, would you perform?

Thank you for your opinions.

First - we do not call w+ with gel. It is either 1+ or negative. The system is so sensitive (as is capture) that if we are undecided if a tube is pos or neg, we call it negative. 1-2+ reactions in tubes with PeG are invariably negative in gel, even enzyme pretreated with PeG (may get some sticky cells but nothing I would call positive). I have found enzyme pretreatment (2 step ficin) to remove many 1+ rxs in gel. My impression is that we are seeing some HTLA activity that is clinically insignificant but is a nuisance. I know I am beating around the bush to your question but . . . I tend to report these out as:"Antibody to the routinely encountered blood group systems are r/o using PeG/anti-IgG. " I identify the presence of a weak reacting moiety using gel technology and recommend ahg xm compatible transfusions. In vivo xm should be considered at the discretion of the referring institution's Medical Director. To date, we have not had any untoward transfusion events. I also may set up a cold screen in tubes using neat specimen (IS, 5' @rt and 5' at 4C) - though colds tend to have a unique expression in gel, the pan-type reactions can cause angst. In your second scenario, I do just about the same, esp looking for cold reactors. However, I also may report the patient as possibly on the verge of some autoimmune process. I noticed phenomena like this when PeG first was introduced. Using gel is a learning experience for all of us newbies (I have been using it for almost 2 yrs now and still finding new reactivities to explain). Both of these "modern" test systems are stretching the boundaries of sensitivity/specificity and we know what happens to one of these as the other is increased. Hope this helps.

We've used gel for 7 years and our followup for your scenarios is very similar to David's, though I don't routinely use enzyme.

I have also been using gel for 2 years- any odd reactions bring me right back to immucor cells, tube and PEG if I suspect an alloantibody.

David Saikin, I am so sorry I can't make your lecture on gel that you are giving at the Fall Seminar, Northeast Conference. People from my lab will be there, hope to meet you on Thursday at the Blood Bank Rountable discussion.

Babs in the lab in Bridgton Maine

We make 0.8% suspension of immucor screening and panel cells and many time Immucir panel gives clear pattern. After all this if no pattern we give gell comaptible units.