Cord blood testing in gel

[sarahk]

For those of you who do cord blood testing in gel cards, do you like it? Have you found more positive DATs? I'm under the assumption that the weak D test can be eliminated--do you have a cut-off where you call Rh positive (i.e. 1+ or less is negative)? Thanks!

[mda]

Yes, we test DAT on cord blood just make sure to wash cells 3-4 times and we never encountered any problem. Any positive reaction (example: 1+, w+) on gel we call it positive. But we flag the patient, to give Rh neg RBC.

[John C. Staley]

Yes, we test DAT on cord blood just make sure to wash cells 3-4 times and we never encountered any problem. Any positive reaction (example: 1+, w+) on gel we call it positive. But we flag the patient, to give Rh neg RBC.

I'm curious, why don't you just call them negative if you are going to consider them negative for transfusion purposes? What happens if they are inadvertently transfused with Rh positive blood? Do you submit a BPD?

[AMcCord]

Gotta give mom RhoGAM even if they are weak D pos, so I would be really cautious about putting a cut-off in place in regards to that. You could still call them Rh neg for the sake of transfusion.

[mrstymt]

I'm relatively new in the field, but I was wondering what the actual AABB Tech manual and Standards say about the "flagging" Rh pos, DAT pos Cord Blood work-up to received Rh neg blood.

Our current policy for newborns have always been to transfuse O neg packed cells for all newborns.

[PaulSunV]

We use Gel for our DATs on cord bloods and yes our procedure it to give only O neg units to a baby. I feel that Gel works well for IgG testing on our DATs

[jlemmons]

If you will rim your cord bloods to remove all of the clots (the nursing staff put them in there on purpose, you know ), then you do not have to wash them. We rim them until we find no more clots, then spin them so we have packed cells , place on the ProVue for an ABO and control (No back type obviously) and DAT IGG. With the new softward Ortho has just put in, there is a clot detection device in the software that will not run (and thus clog up) your ProVue if you have missed a clot. It works great on our cord bloods.

[bbonnema]

We have great luck with them as well. We take a small portion of the cleanest cells we can get and centrifuge it and take the top portion of those cells and put that in the testing tube.

[David Saikin]

I do not wash my cord bloods and have had no problems with gel testig, but my cords come in EDTA tubes. You need to do a weak D when using gel cards as the anti-D will not detect DVI, which is antigenic enough to elicit an immune response. I do the weak D in IgG cards with my tube anti-D and also run the Rh control.

[bbonnema]

Do you have a procedure for Weak D in Gel that you could share?

[David Saikin]

Basically - I prepare 0.8% red cell suspension from the cord blood. 50uL in 2 gel IgG tubes. 25uL anti-D in one and 25uL of D Ct in the other. Incubate 15 minutes at 37C. spin/read. I use my screening cells 2 and 3 as controls with each event (usually only 1-3/month). Ideally you could run a DVI cell as the pos ct but I do not.

[Auntie-D]

We've never had any problems. Babies are classed as Rh neg for transfusion purposes and mums are given prophylaxis. All babies are types and their group amended on receipt of the results.

[crldehart]

I do not wash my cord bloods and have had no problems with gel testig, but my cords come in EDTA tubes. You need to do a weak D when using gel cards as the anti-D will not detect DVI, which is antigenic enough to elicit an immune response. I do the weak D in IgG cards with my tube anti-D and also run the Rh control.

We also do not wash the cord blood. We check all specimens for clots before putting them on the Provue, even with the new software. Negative anti-D tests on the cord blood are followed up with Tube Weak D tests (for mom's RhIG candidate evaluation).