Our Blood Bank has always performed the DAT by tube method (the exception being cord bloods). We do the Poly and if it is positive, then we do the IgG and complement. Recently a patient presented in the ER 5 days post-transfusion with a 4.2 HGB and a positive antibody screen. His autocontrol was positive as were most of the panel cells. His Poly DAT was negative. Due to the patient's symptoms I still highly suspected a delayed transfusion reaction. Our reference lab agreed to see what they could figure out. They only perform the IgG DAT and they perform it in gel. They got a strong 1+ and their eluate showed an Anti-e.

Needless to say, this caused me to doubt our previous method of performing these tests. I was able to validate performing non-cord blood samples on our Erytra and would prefer for this to be our main method for doing these. I previously was looking into getting rid of the complement portion by default (i.e. Poly - Pos, IgG - Neg) because we use so little of it that it is a big waste of money. We often throw out complement check cells that have never been opened. However, now I am looking at getting rid of the Poly and just doing the automated (gel) IgG and tube complement. I see my choices could be  the following:

1. Eliminate the Poly and perform the automated IgG and tube complement on all DAT samples

2. Perform the automated IgG and, if positive, perform the tube Poly and default the complement

I want to be sure that my decision is acceptable to the AABB and CAP, hopefully save some money for our department, and still maintain proper patient care that the physicians will be happy with.

Any thoughts and/or suggestions on this would be greatly appreciated!

We do only the IGG in gel or tube and C3 in tube.

The Poly has proven unacceptable.

We dropped the poly for the same reasons you are considering.  We have an Echo and perform ours on there and have tube reagents for backup or in case the sample is too small to run on the Echo.  We are AABB accredited, but not CAP (we use HFAP) and our processes have not been questioned by either agency.

limper55 - Just out of curiosity, why was the Poly considered unacceptable? What manufacturer were you using?

CAP says you have to be able to detect complement when you perform a DAT (exception - cord blood). So you would need to do the automated IgG and tube for C3 to satisfy CAP.

I use manual gel for anti-IgG and anti-C3b,-C3d. 

David, How are you doing the anti-C3b,-C3d in manual gel? Thank you

1 hour ago, Gerald said:

David, How are you doing the anti-C3b,-C3d in manual gel? Thank you

We perform it using the buffered gel card and add our anti-C3b,-C3d.  These are done mostly on cord bloods.   We run controls w each event.

25 uL  anti-C3b,-C3d,  50 uL  0.8% patient cells?  Do you incubate before spinning?

Thank you

5 minute incubation

Thank you David

The DAT MIGHT have a considerable IgA component.  Some anti-IgG (and hence also poly) will pick up IgA more than others regardless of method.  

A photograph to back up galvania's comment.

IgA DAT.pptx

On ‎09‎/‎03‎/‎2019 at 10:43 AM, Malcolm Needs said:

A photograph to back up galvania's comment.

IgA DAT.pptx 362.64 kB · 15 downloads

I'd love to be able to get these cards in the USA.  However, they are not available for us at this time.