Hi all, we have a very loosly written procedure for resolving discrepancies between forward and back types that I am detailing. There has been a common, undocumented process here where cord blood cells are used to back type a patient when the patient has a strong cold autoantibodies to eliminate the interference of an Anti-I. Cord cells of the same forward type of the patient are used with the patient's plasma to substitute for the commercial A and B cells.

 

I can't find any specific procedures for resolving ABO discrepancies and our local Reference Lab does not do back types with cord cells. We don't do absorptions or enzyme testing or anything "fancy" here. Do you think it makes sense to continue with using cord blood cells as a back-type cell when auto Anti-I is suspected? If so, I will write a procedure but I wanted to run it by you first. My goal is to get rid of all undocumented practices and provide the staff with genuine procedures for these uncommon scenarios. Thanks!!

Seems very reasonable to me.

My goal is to get rid of all undocumented practices and provide the staff with genuine procedures for these uncommon scenarios. Thanks!!

 

Bravo.

Thanks to both of you! I could make a career out of looking at processes in blood banks and setting them "right". Tons of fun!

I agree - a great idea!

But why do they use "cord cells of the same forward type of the patient"?  It isn't much of a reverse type if the patient is O.  Or do you mean that they use cord cells to verify that there is an anti-I and then something else to get a viable reverse type?

A few not-too-fancy thoughts: Since you seem to have access to baby cells, make pools of washed A, B and O cord cells. Your panel manufacturer may supply a vial of their diluent, make suspensions in that every month. Otherwise make fresh ones weekly or as needed. You can do a "mini" cold panel with screening cells, patient cells and O cord cells:

Screening cells react but not cord and patient cells: probably anti-IH. (Probably won't muck up your back type much, either).

All cells react except cord: autoanti-I. Use A and B cord cells for back type.

All cells react: cold autoantibody other than auto-anti-I. See below.

Or, easier, just warm your back type tests (and ab screen done the same way as a negative control) at 37o for a few minutes and respin. Most spurious IgM antibodies will stop reacting but anti-A and anti-B will usually keep reacting. You may need to do a real prewarm technique.

Howdy!

 

As per Dr. Pepper's post, we utilize pre-warm techniques to resolve cold antibody interferences in the back type.  I do not personally have any experience using cord cells in addition to or as a replacement for pre-warming.

 

Best of Luck!

OneMore

Years ago there was a cord cell on a commercial panel we routinely used as an I negative cell. Since we did so much room temperature testing, it was useful for cold antibodies & ABO discrepancies. After it was no longer on the panel, I started pre warming & just saying the problem was due to a cold antibody.

I think most manufacturers used to have them. I was told they stopped doing that with the advent of HIV testing on reagent cells, and sticky issues getting permission from the moms to test the babies. Don't know why they wouldn't have had that same issue with hep testing, though.

Sorry its taken me so long to say thanks. I got caught up in getting ready for Echo, plus vacation, and lost sight of this post. For the moment, I revised the existing procedure to say to use washed cord cells of the same type as the adult patient and test the plasma against the cord cells to eliminate Anti I. I threw out the references to Anti H, no idea why that was in there to begin with. I may revisit this procedure soon but for the moment, I am working on DAT, algorithms for ABIDs etc. So much thinking to do that my brain hurts