Mabel Adams

O neg units are no panacea for antibodies unless the specificity is for ABO or D. The worst scenario I can think of is a mom with a really high titer of say, anti-S, that was passed to the baby via placanta. Baby would have to be S neg or it would have stayed in the hospital recovering from the HDFN till most of the maternal antibody was gone. Then, if there is a trauma and if you transfuse this baby with S+ blood, you could get a hemolytic reaction--self-limited since no more antibody would be produced--but not particularly helpful in an already gravely injured child. Odds of this are extremely remote due to the rarity of moms with high-titer antibodies having babies that are antigen negative and are then involved in a trauma. Aren't babies under 4 months considered incapable of making new antibodies? Then you wouldn't have to worry about any that the baby could continue to make, at least till later. Maybe that was your point about continuing with O neg units??? We had a tragic case of post-partum depresssion where the mom shot 3 of her kids, including the 2 month old and 3 & 5 yr olds. One died with the mom, but the baby and the 5 yr old made it in to us. We got a specimen from the baby that was venous, but they had an IO in that they used for infusion before they shipped her out. So this question is not just for children's hospitals but could come up anywhere they might use IO for access. I don't know if it was the right logic, but I chose to give her O neg blood even though she was A pos and I had time to crossmatch so the receiving hospital could use the < 4 mo./only given O/ need not crossmatch or retest till 4 months old rule. I think I would be tempted to use it for the type--at least for the record--even if you continued to give O red cells.

Next question is on cryo for premies. We have instructions to add 10 cc of saline to a single cryo unit after thawing for a neonate. Is this common practice?

Wow, Gil. What a great posting on DATs. I am going to email it to some newbies as a great source for their education.

I was relieved a few years back when working with an OB with a warm auto to learn that such antibodies, if benign in the mom, are usually benign in the baby. (That's buried in Issitt somewhere.) Although interesting, it sounds like it is a non-problem clinically--expecially with the previous baby being okay. I wonder if the antibody remained between pregnancies or if it comes back with each pregnancy. Maybe she will volunteer to be checked 6 mo. post-delivery. Can't antibodies with lower avidity sometimes be partially washed off in the washing phase of tube testing? Since gel is not washed, maybe that helps explain the strength difference--the antibody is lower in avidity. Hope you don't need to transfuse her. She would be compatible with Ce neg units and you would expose her to Ec pos units by giving compatible units.

Does anyone know if all the sterile connecting devices out there are compatible with all the syringe sets? I can find SCDs made by Terumo and Haemonetics. Are there any others? What is everyone else using for an SCD and are you happy or unhappy with it?

Also, does anyone have any experience with the Genesis BPS syringe and filter sets? Are they just like Charter Medical's?

Does anyone know of an X-ray blood irradiator in which syringes will fit? Who makes Xray blood irradiators anyway? Just the one company (Raycell I think)? Also, does anyone know of a source of such an instrument as used equipment? I heard of someone that bought one a couple of years ago that was used and the price was much more possible. I might as well dream, right?

If you are doing gel titers you need to have informed your OBs that the titer values in their books won't correlate to yours as far as clinical outcomes. Gel titers of 16 could cause unnecessary amniocenteses without this notification.

Has anyone with the newer Massive Transfusion Protocols that include plts and FFP with the red cells as soon as possible found a reasonable way to issue their "bucket-o-blood products"? We won't have pre-thawed FFP so it will likely go out a little later than the red cells and plts. It seems like it would be good to keep it all together but we have temperature issues between red cells and plts and even freshly thawed FFP might be too warm to put in with red cells. So, any creative coolers out there?

Thanks Kay. Do you ever give plts to neonates? We might have to do that rarely. We don't have a sterile docker at this time and our supplier is 6 hours away, barring weather issues, and does not make plts from WB donations. If it is rare enough, we will probably just sacrifice an entire pheresis unit. Does anyone have pro or con on the Genesis Pedi-syringe Filter syringes and filters?

I would turn these out as "too weak to titrate" if tube testing of neat sample was < 1+ in tube/saline/IgG. One could also say "Titer < 1" which is what I did if I had gone ahead and done the titer and it came out neg (or <1+) in the first tube.

I have just changed jobs and moved to Oregon. They are ramping back up to a level III NICU here and we are to meet with the new neonatologist. I have some questions for you with NICU experience. Do you worry about giving Rh neg plts to female neonates that are Rh neg or do you consider their immune systems too immature to make anti-D that could affect them in their child-bearing years? What do you do for emergency transfusion of plts to neonates when your usual stock of AB plts in unavailable at the moment you need to transfuse plts to a baby with unknown or non-O type? We do not have the ability to volume reduce. Obviously we would use type compatible if available, but what if the only products available are plasma incompatible? Do you leave it up to the doc whether to wait for some to come in (6 hours) or give plasma incompatible? Can you direct me to a good source of filters and syringes to use to aliquot red cell and plt units in the BB? How would you validate these? What is different about saline that is labeled "safe for neonatal use" compared to Normal Saline? How long do you use an irradiated unit for a baby after it was irradiated (my reference says due to K+ increase, they should be given ASAP)? Recommendations for sterile docking devices also appreciated. Thanks

I think Galvania covered this pretty well. Too bad our terminology and reagents don't really correlate with the biology. Weak D is a misnomer for a partial D that types 4+. We have changed Du, weak D etc. terminology at least 3 times in the past 30 years; maybe we should make another try that fits the situations better--or should we wait for molecular testing to clarify things?

Although we allow 2 single-dose K cells, we must not fall into the belief that this is actaully more sensitive than one single-dose cell. Due to dosage, a double-dose cell may be more sentitive. But using 2 single-dose cells reduces the likelihood that an anti-K will be missed because one of the K+ cells did not react due to technical or other difficulties. Statistically, anti-K is a very common antibody so it is worth some extra effort to make sure it is not there.

I will tell a story if it could help someone else. We used to wash our cell suspensions for fetalscreens (and for everything else for that matter). I would decant the washings by holding more than one patient's tubes in my hand--usually some prenatals I was doing along with the fetalscreen. On several occasions I got similar results to what you are finding. I figured out that the other tube in my hand was always an Rh pos patient. When I flicked my wrist at the end of the decant, I must have splashed a miniscule amount of Rh pos cells into the fetascreen cell suspension. This was never enough to show up in any other kind of testing I did on it, but it did cause some rosettes to form. When I would repeat the fetalscreen on a new cell suspension, it would be neg. This might not be your problem. What do you find when you repeat the same and new cell suspensions on your fetalscreens? I have another theory since many of us use EDTA for ab screens now. Fact: reticulocytes will end up on the top layer if you spin a sample down in a capillary tube. Fetal blood is more likely to have retics (and bigger cells that are somewhat like retics), so if we don't do fetalscreens and Kleihauers on well-mixed samples, could we pull the fetal cells off first? We draw our fetalscreens in purple tops instead of the pink tops we use for gel testing just so we don't spin them down out of habit, then sample only from the top layer of cells when we make the suspension.

I have been trying to order anti-C monoclonal from Immucor and find that it is backordered indefinitely. I am guessing that it is backordered till the price increase is in effect, but maybe not. Does anyone know what is going on? Gammaclone control and anti-IgG green are also backordered. I can get by without these for awhile but I am about out of anti-C Anyone know of a source of monoclonal anti-C that uses the same testing steps as Gammaclone (IS & 15 min RT)?

The denominator is total cells in our calculation.

Good point. I must admit I am going from memory and didn't think that part through particularly. They might have estimated the residual from flow cytometry (D antigen) or even repeat fetal screens or just D typing.

We do it every time based on the KISS principle. Then new techs and generalists don't have one more set of exceptions to remember. It is quick, easy and cheap. Complement him on his higher understanding of serologic principles then tell him to do it anyway just to keep things simple and consistent. Put that brain to use thinking about something that can make better use of his intelligence! I bet he would be good at making suggestions of ways to improve processes--changes that could be written into SOPs that everyone would follow consistently. Changes that would make more difference to the end product than tilting at this windmill. Sorry, got going a bit, didn't I?

What if a patient presents a donor card with his blood type on it? Would we accept that? If so, how would we document it. In fact, documenting any outside type in your computer system might be what determines what you will accept. Computers often run out lives!

The clinical situation would have impact but even with something chronic like myelodysplastic syndrome, you'd think the doc would want to see if they are even lower. Most other situations might have mitigated themselves over 4 weeks making transfusion unnecessary or even dangerous. In a chronic outpatient I don't see how you should go back more than about a week--less if more acute causes are implicated.

We went to diluting our own screening cells (Immucor's) to 0.8% and our false positive rate in gel is now quite manageable.

I wonder if the second tech forgot to put serum in the IS xm tube. The volume would have been low, but if she were distracted enough she might not have noticed it.

We have two main concerns: Bacterial growth if unit contaminated and factor degradation. Plt in closed system can be stored for 5 days at room temp, but we know they have a higher frequency of transmitting bacteria to the recipient (unless the newer approaches have improved this). Plts are so precious that may be an acceptable risk not willingly taken on for FFP. There is now a good bit of research about factor changes over time, but I am not sure it includes much with room temp. storage. This would be a good SBB project, no?

We don't repeat types for add-on orders, but our policy requires checking that the band number and patient ID match for specimen currently used and specimen on record. Also our computer keeps all add-ons on the same specimen number for the life of the specimen (3 days) so it is easy to make sure we are using the same specimen. We do a DAT or Auto control only with Ab IDs, not screens. We are an independent lab serving 2 hospitals that total about 150 beds.