[antibody to reagent cells]

6 hours ago, jemarass said:

Hello!

We had a patient this morning have a positive antibody screen, so we sent her off for antibody ID which came back negative. I repeated the screen from the original sample and obtained the same results, had the patient redrawn and again same results. We use quotient screen cells, where as our blood center uses ortho. Has anyone come across a case where a patient has an antibody to the reagent? Was this proven in anyway? Patient has an order for 2 units of blood but with no specific antibody available to screen for, I am stumped as to how to call it a compatible crossmatch if we don't know what is causing the positive reactions.

Thank you!

Yes you can for sure have an antibody to a reagent.  I have seen it a few times against 0.8% Ortho reagents in GEL.  We still primarily test in tube at my reference lab but when I do go to GEL, I tend to dilute out 3% Immucor cells instead of using the Ortho 0.8% cells to avoid any issues.  I know in your case Ortho cells were negative but can definitely be directed against quotient cells. 

[DTT-Treatment of Screening Cells (Daratumumab/Darzalex)]

6 hours ago, applejw1 said:

The Hemo Bioscience 0.2 M DTT comes in 2ml vials - the ratio listed in the Technical Manual is a 1:4 ratio - 1 drop of packed red cells to 4 drops of 0.2M DTT. Incubate at 37 and then wash at least 4 times with 0.9% saline.

I would definitely suggest using 2 drops of cells to 8 drops of DTT.  You will lose cells in the washing process.

[DTT-Treatment of Screening Cells (Daratumumab/Darzalex)]

I work at a reference lab and I have personally worked up many Dara patients. I have had to DTT treat reagent cells only once to remove the reactivity caused by it.  Every other instance I have been able to complete rule-outs/rule-ins in LISS.  Maybe as these patients are on the drug for longer we will have to start DTT treating cells more but as of now it hasn't been as big of an issue as it was thought to be last year when this all started(at least for us).  Has anyone else noticed this too?  Could be we are just lucky with our patients.