Our cord blood screen procedure, which was in place when I took over as senior tech in blood bank, has always stated to make a 3-5% washed cell suspension to do the ABO/Rh type and then wash cell suspension an additional 8 times before adding reagents for direct coombs and a control. I think this is over kill, since washing it 4 times, then adding reagents results in a negative control. (If the control were positive, then additional washes would be necessary).

Our cord bloods are collected by nursing with a needle and syringe and placed into an EDTA purple top tube. The technical manual also states that collecting with a needle and syringe avoids contamination with Wharton's jelly and the need for additional washings. I know the reason behind the "8 washes" was to wash away the Wharton's jelly, but with EDTA tubes, I've not seen any interfering substances. Plus, I cannot find a reference to wash it 8 times, just the tech manual now stating that additional washes are not needed if collected with needle and syringe.

So, with all that being said, what does everyone else do? I'd love to change it make a 3-5% cell suspension (no washing needed to do the ABO/Rh type) and then wash the cell suspension 4 times and then add the reagents for the direct coombs and the control.

Thanks

Natalie

---

Make a 3-5% cell suspension (no washing needed to do the ABO/Rh type) and then wash the cell suspension 4 times and then add the reagents for the direct coombs and the control. There is a note that if the control is positive to repeat with 8-12 washes.

We do all our testing using automation unless the specimen is clotted. There is no washing involved there. If we do manual testing, we just make a cell suspension with no washing.

Make a 3-5% cell suspension (no washing needed to do the ABO/Rh type) and then wash the cell suspension 4 times and then add the reagents for the direct coombs and the control. There is a note that if the control is positive to repeat with 8-12 washes.

Any reference besides current technical manual?

- - - Updated - - -

We do all our testing using automation unless the specimen is clotted. There is no washing involved there. If we do manual testing, we just make a cell suspension with no washing.

We are still manual tube testing, no automation here yet

If you are using monoclonal ABO antibodies, there is no need to wash.

If you are using human ABO reagents, there is a need to wash.

For the DAT, wash four times.

Just AABB and the current practices in the area.

If you are using monoclonal ABO antibodies, there is no need to wash.

If you are using human ABO reagents, there is a need to wash.

For the DAT, wash four times.

They are monoclonal for ABO antibodies

Then no need to wash.

We only wash if we have dispcrepancies - use gel.

Even in the "old days" we only washed 4 times unless there was a problem

Current (old) policy had us perform the aborh and set up DAT and DAT ctl at the same time - in case DAT is needed. Make a 3-5% solution and wash all 6 tubes at the same time...seemed to save time by doing it all together....guess we don't need to...

We make a cell suspension and place 2 drops in 5 tubes and put them all in the cell washer. Wash 4X. We do a DAT on all newborns. Seems like a lot of effort to divide up 5 tubes regardless of the reagents. A couple of times a year out of 1500 babies do we have to wash more than 4.

I'm not sure if I am following the DAT descriptions correctly, but I remember having debates in the past over whether you could wash a cell suspension X number of times, place a drop of these cells in a tube and just add the antiglobulin reagent or whether you had to wash that drop of cells at least one more time to a dry button before adding the antiglobulin reagent. It seems that I recall that the manufacturer's instructions implied that you had to wash it to a dry button. What is the consensus and has anyone tested it both ways?

We don't centrifuge to a completely dry button. There is always a little saline left on the cells.

We make a 3% suspension of unwashed cells for the ABO and RH and wash a drop of cells in the cell washer 4 times for the DAT. If our ABO and RH looks grainy then we might wash the cells 4 times and repeat.

Malcolm, are you talking about a single drop of cells washed the last time still having residual saline (what I was loosely calling a dry button--even though you had not blotted off the residual saline or anything) or are you talking about a drop of cells that is around 3% cells in saline. Or does it matter? The instructions always say, "Decant completely after last wash" which suggests to me that they don't intend for us to use a drop of 3% cell suspension to which we add AHG. But maybe that statement is in a different context and I am being overly narrow in my interpretation. Now there is an easy SBB project?!?!!

Sorry Mabel, my fault for not being clear. I meant just residual saline (not blotted off), rather than 3% cells in saline.

we make 3%(this is with measured saline and packed cells) suspension from CORD pack cells and then take one drop of that suspension and wash it X3 in cell washer, then add 2 drops if antiglobulin reagent, spin, read, if negative read microscopically.

Then no need to wash.

No need to wash the RBC.

I stopped washing when we went over to gel cards but my colleagues began to complain.

We routinely test unwashed cord blood samples on ProVue without any problems.

We do our cord testing in tubes. I wash once, just to make sure all clots etc are out (nurses are notorious for not inverting the EDTA tubes). This initial suspension is used for ABO and Rh testing. If the Rh needs to be taken to IgG, I then wash a drop of the suspension 4 times, decanting to the "dry button" each time. The same is done for the DAT.

We also test unwashed cord blood samples on ProVue with no problems.

We routinely test unwashed cord blood samples on ProVue without any problems.

We also test unwashed cord blood samples on ProVue with no problems.

Same here.

Wash 6 x no cell washer. Works for me

We wash a suspension of cord red blood cells maunually 3x.

From these washed cells we do an ABO and Rh type in tube.

Also, from the washed cell suspension, 1 and 2 drops of it are

placed into 2 respective tubes, wash 3-4 times in the cells washer

and then add 2 drops of Anti-IgG to eaxh tube for the DAT.