Dr. Pepper

Hi Amy, welcome to the site by the way. I ditto what Mary and Malcolm said. He could also be an A3B. A2B or A3B, he should also show reactivity with anti-H. I would not consider this a typing discrepancy as your front and backtype match; the reagent anti-A is just a bit weaker than expected. In any event, there is absolutely no reason not to give him AB. Give him enough A1B, and you might even get that anti-A reaction up to 3 or 4+! Phil

OK, the only magic to the "3+3" rule is that if you plug those numbers into the horribly unwieldy formula for Fisher's exact method of calculating probability, you will get a probability (p) of 1/20, or a 1 in 20 chance that the reactions could have occured by chance, or a 95% confidence level that your conclusion is correct. (This is a totally arbitrary number by the way.) Lower p values (1/15, 1/9 etc) allow for too much chance of random association. Higher values (1/28, 1/56) show that there's a much smaller chance that your conclusion is incorrect. But there are other magic combinations that will give you an acceptable p: 5 and 2 (1/21), 4 and 3 (1/35), 6 and 2 (1/28) and so on. You do not necessarily need 3+3. See Goodchild's reference. You run into problems when you only have one positive or negative cell: 7 and 1 (p of 1/8), 8 and 1 (1/9), etc. You would have to get to 19 and 1 to get the magic p of 1/20. If you think about it non-arithmatically, what if your one reactive panel cell is also positive for an unlisted low frequency antigen? What if your one negative didn't have serum added or isn't reacting for some other technical reason? So you don't necessarily need 3 Cw+ cells; 5 or more neg and 2 pos would suffice. And you don't need 3 Js(b-) cells; 19 pos and 1 neg would be OK statistically. The problem I see with the high incidence antigens like this would be that with only one negative cell with which to rule out, you would still have a bunch of other antibody choices you would like to rule out, hence the need to test more negative cells. So, pedantry aside, the bottom line is "don't base your ID just on the reaction with one cell". A second cell of similar makeup coupled with the pos or negs from the rest of the panel should bump your p past 1/20.

We also use next business day if the workup is negative. If there is eveidence of a reaction, the patient's MD is notified ASAP.

Anna pointed out that they wouldn't have had a hint of the antibody had the patient been group O. So this then becomes an acceptable risk of transfusion, like the 1 in 10,000 incompatibility that would have been caught by a full crossmatch but missed by IS or electronic when the patient has an antibody to an antigen not on the screening cells. It's interesting what we consider acceptable or not. Our industry spends a lot of money shaving very small slices off of very small piles of risk - like WNV testing, for example. But we accept other risks, like the above, or possible hemolysis from minor side incompatbile platelets and so on.

I think Malcolm's point was that they didn't do a panel when they noticed the typing discrepancy, but just assumed it was an insignificant cold because their solid phase screen was negative. Had they done a panel in tube or gel, they would have seen it, and probably seen a positive auto control, and done the DAT....I'm a little confused about the DAT - where did the IgG come from? Eluates were negative. They investigated a possible drug antibody but that didn't turn up anything.

They say it reacted at all phases with LISS, with PeG and gel methods and showed in vitro hemolysis by tube. The patient had received 2 Le(b+) units 9 days earlier, got a nice, expected bump in hgb, but was anemic again and was given the unit she had the reaction to. The backtype discrepancy was noticed before the last transfusion but chalked up to a cold agglutinin and not worked up. DATs were 1+ IgG, 2+ C3 before, 1+ IgG, 3+ C3 post-rxn. They report the antibody was IgM only with a titer of 256.

Mabel, I'd be happy to send one if you need one. (And that credit card-sized flash drive is so cool...)

Must be why those antibody activity charts say "usually" and "rarely" instead of "always" and "never". Interesting article; thanks, Malcolm.

I should add that our test profile also includes the unit DIN and amount returned. We also have a blood culture reflexed.

Having recently had firsthand experience, I can attest that Mr. Needs is a paragon of moderation.

Don't have that lot, but you could let Immucor know what your issues are. If enough people complain that they're getting a lot of unexplained reactivity with a cell they can get it out of the screening cell rotation.

Whatever squeamishness I had was cured during my Peace Corps days in West Africa. We had porcupine, bush rat (agouti), and offal from various critters. I did not try the smoked bats (maybe a good thing, since I've found out since that there was an endemic strain of Ebola there). And I looked at dormice on Wikepedia - they look like a cross between a mouse and a squirrel. Must take a bunch to make a meal, though.

Tastes like chicken......

I wasn't going to mention this, but since someone ELSE did, this was also in my lecture......

Mine as well. I'm sure Mari and staff did a splendid job. But that's a blood banker's nightmare - and a parent's, student's, relative's, friend's, educator's and everyday American's nightmare as well. Far too many of these of late.

We have a test profile that includes clerical check, exam for hemolysis, DAT, typing, pathologist interp. We answer the first 4, the pathologist the last. Goes on the chart and in the EMR like any test.

From the anti-Sd(a) part of my antigen systems lecture.guinea pigs.pptx

As an addendum, what we do with anti-Sid (love the janitor story by the way) is: Look for the unique "Sidish" appearanceTry to eliminate other ab choices per routine panel techniquesDo the urine neutralization on all reactive reagent cells to make sure the rxn go away with the urine but stay with the dilutional control.Find full XM compatible units with straight serum/plasma - usually not too hard.Many panel manufacturers will also indicate cells that are strongly Sd(a+) which can be a clue to what you're dealing with.

My line was always as hard as it is to catheterize a guinea pig, it's even harder to train them to pee into those little cups......... The procedure in the tech manual says to use freshly collected urine and boil it first. Do any of your reference lab types (ahem Malcolm) know what this step is for? It sounds like the start of a secretor study, where the boiling inactivates salivary enzymes that might start to digest your soluble blood group substances. I have happily used pooled urine from 5 or 6 urines with a neutral pH and it seems to work just fine without the boiling, and without dialyzing for that matter. Any danger in this? Thanks - Phil

I'm assuming they are being issued in a cooler, which is in itself a bit of a compromise in storage (no alarms, possibility of removing it and leaving it around at room temp). I'm not aware of specific regs that forbid the issue of multiple units in properly prepared and validated coolers etc. For me, the big issue would be lack of control and oversight of the units. The more units you have outside of the blood bank the more opportunities there are for bad things to happen to them. You are taking more risks so that nursing does not have the very minor inconvenience of sending a gofer to the lab or requesting a unit be tubed to them a couple of hours after issuing the first one. I would stick to my guns. It's your blood, and the very best place for it to live is your refrigerator. We only issue multiple units in coolers to the OR. We have a contingency to do so in the ED but never do (we don't get trauma patients). I would do as Dansket does.

Sorry, couldn't resist that. We have indeed retreated further into the basement lab. We used to draw the morning blood. Then lab-based phlebotomy teams did so. Then RNs. Now barely trained CNAs are doing so. The specimens took a quality hit with each of these steps. I think that the upfront involvement you seek is what you can do yourself and what you are fortunate enough to be able to do within the framework of your particular system. Some things you can do: We monitor specimen quality and misidentifications and report to the hospital QA people. I work with the nursing education staff who sincerely want to make sure their staff does what it should, and knows the "whys" which makes buyin for the "how-tos" much easier, and in the process complies with CAP and AABB. We have to remind the ever-changing nursing management to get lab input when revising lab-related nursing P+P. Your transfusion committee should be a good forum. In short, it's communication and cooperation between departments, and forging some relationships along the way where docs and nurses realize that we are the experts and, if not seek, at least respect our knowledge and opinion. I think over recent years there has been an increased desire around most institutions to "do the right thing" in all areas of patient care. It may be a bit more indirect than being a physical presence as a member of a transfusion team, but there are still opportunities for the lab to aid in process improvement.

You could always marry a nurse.

I will keep looking at BBT, although maybe not as often. I'm going to offer myself to CAP for a few freelance inspections, and will keep active in our regional chapter of ASCLS, at least for a year. It's funny, for the past several years people have been asking me when I was going to retire (hopefully not infering IT'S ABOUT TIME), and now that I've picked a date, everyone is coming up with things to do/be: part time, per diem, consulting, etc. To me Retirement = Not Working Anymore!

Ditto ditto ditto! Half the time, half the price, half the work. Doesn't smell like skunk juice. What's not to like? Don't worry about a loss of sensitivity - you're still testing in PeG at the end of the day. As Malcolm has pointed out, we weren't killing patients right and left in the half century before gel. Tube be or not tube be.......

Damn, I've still got 7 months (well, six and a half, not that I'm counting!) before I retire. Good for you.