sbraden

We see this fairly often from our hospitals. Often the reactions have an abnormal appearance, as in they have mixed field or uniform haze through entire column, but the auto-control is negative. Usually we run a converted panel from another manufacturer and 4-6 random units. All of this testing is usually negative.

I am going to make an assumption, (which I hate doing) and assume the part you saw shaken was the actual collection bag, which is surprisingly small. Shaped like a long rectangle? If it was an amicus system the manual actually calls for 2 re-suspensions before mixing into the plasma collected. The phleb will hold the bag firmly, with no slack between their hands and shake it lengthwise rather vigorously. The first time I saw this I curiously asked about it since I knew we usually treated them gently. Once it is suspended in plasma it sits "x" amount of time then is sent down to process lab. If you do not shake it enough, the platelets will not release from the small bag and you will have clumping and even low-yield products. I had the exact same "What are you doing!?!" response. Some machines, like the Trima I think, will do the agitation internally. Hope this helps.

I work at a blood center and I can tell you that though super rare, mislabeling does happen. Not sub-groups, or variants, but actual wrong blood in the wrong bag situations. I have only seen a very small number of these and they always involve the most unbelievable, bizarre, "were they TRYING to mess up" situations. These situations usually result in 2 first time donors having their blood drawn into a bag labeled with one number and the tubes labeled another number, now both bags have the wrong blood/label. First time donors do not have history to catch these discrepancies. I would never suggest the confirmation step at the hospital be removed, especially with electronic XM so prevalent now. I guess it's been at least 6 or 7 years since we had one of these.

We frequently get samples on recently transfused patients that the hospital says have a negative DAT. Our DAT in Gel will be +/= and maybe a few +/= reactions in the neat plasma. The eluates often have easily identified antibodies with strengths up to 3+ in Gel. When we call the hospital to give report, we have been told several times that they gave crossmatch compatible blood before our work was complete. We sometimes perform eluates on negative DAT samples if it "makes sense" to us. Usually it's when we say to ourselves, "This might be a weak warm-auto if the DAT were +".

The original question was for all DATs, and this is from a reference lab perspective. We us Quotient for all three reagents. We use CAP. No we only VERY rarely use the scope, and it's at 10x rolling a tube and it's just for informational purposes. We also perform our DATs in Gel, with a significant difference between reaction strengths. Many times the tube is negative and the Gel is 1+ or 2+, so weak reactions should be caught there. Many identified Abs in eluates from tube negative, Gel 1+ samples. We HERE define optical aid to be a lighted mirror for tubes or laying the gel cards on an old school view box. (that doesn't mean it's the right way, just our way) We have made an addition to our SOP to never use a mirror to read Gel cards. We allowed one tech to do this for almost a year and the amount of extra work was staggering with not a single clinically significant Ab identified. (that doesn't mean it's the right way, just our way) We don't use the scope because after many years of experience, (here) we determined that we were not viewing anything of clinical significance. I think that is the key, you have to balance risk/reward. If you use the "we have to do what's safest" theory, then you might end up running full panels and FICIN panels on negative screens.

As someone that works in a small blood collection facility, my first thought was how did this get through testing. Then I realized the problem is probably related to the antigens, not an antibody. First thing we check is DAT of the unit, which is negative. Then we would test against a couple of random samples from each compatible blood type, which you did. Then I would do a more elaborate ABO, which if there was a problem should have (in theory) been caught during testing. Then I thought about your reactions, 4+ tube, 2+ Gel, that's backwards from "normal" reactivity. Here we see a difference in reactions of at least one, usually two levels higher in Gel than tube. Unless whatever is happening is more IgM than IgG....... Then I think, do we all have Nabs that would react to some super low-incidence antigen? That was literally my thought process in 2 minutes, with no logical brakes. LOL. I'm not knowledgeable enough with this off the top of my head, so now it's time to read. Please post what the supplier says.

Thanks guys, I actually was on here a little about 75 years ago it seems under a different account. I couldn't remember the login or password. Opus something....lol.