Malcolm Needs

I wouldn't worry about the "missing" anti-A, as weak ABO antibodies are comparatively common amongst elderly patient's (and those in the FFP would disappear from the circulation fairly quickly). I would give her cross-match compatible group B, D positive (assuming that she has no atypical alloantibodies at 37oC). If you want to see if this lady really does have anti-A, try incubating the reverse group at 4oC, and/or treat the reverse typing red cells with a proteolytic enzyme such as papain (but don't forget to run controls). :):):)

As the patient has pneumonia, I would think that there is a pretty good chance that there is a "cold-reacting" auto-antibody (probably anti-H, anti-HI, anti-i and/or anti-Hi) present. Have you tried performing an auto? As JOANBALONE says though, there is also a good chance that the patient is an A2 with an anti-A1. Either way, unless the antibody reacts strictly at 37oC, and there are no atypical alloantibodies present reacting at 37oC, there is no reason why you should not give group A, D Positive blood that has been found to be compatible at 37oC. :):)

That is fantastic! :D:D:D:D

I'll do my best. For those of you less familiar with the Law of Mass Action, could I suggest you go to the top of the page and click on References, then Document Library in the drop down list, then click on User Submitted, followed by Educational Materials, then choose the PowerPoint lecture on Antibody/Antigen Reactions and look at Slides 7 to 9. You will see from this that there are two reaction constants. One of these (k1) drives the reaction that sends the reaction from the concentration of unbound antibody and unbound antigen towards the concentration of bound antibody-antigen. The other (k2) drives the dissociation of bound antibody-antigen towards unbound antibody and unbound antigen. Obviously, in the Blood Transfusion Laboratory, where we want to detect the presence of clinically-significant atypical alloantibodies, we want to drive the reaction to the right (i.e. have a dominant k1). The k1 of strong antibodies that have been diluted to give weak reactions will be more favourable to sending the reaction to the right, than a genuine weak antibody. Therefore, if a diluted strong antibody is used for the positive control, you may well be giving yourself a false sense of security, as this control could give positive results, whilst genuinely weak antibodies that may be in the patient's plasma may be missed (give negative results), because the k1 and k2 reaction constants are not at a serological optimum. Off the top of my head, that's about the best I can do, but I hope it is of some help. :):)

I did also say, however, that a positive DAT with IgG and C3d is exceptionally rare, and may not be any more clinically-significant than IgG only, and so I would be comfortable if anti-IgG only was used. :):)

I was at home using my lap-top in an attempt to get out of the washing-up (I had cooked the Christmas dinner - full trimmings). This attempt failed miserably!!!!!!!!!!!!!!! :(:(

Yes thanks Steve. Even my Mother-in-law liked them. :omg::omg:

The thing is though, with the surface area of the tips, compared to their volume, and the fact that they are made of plastic, which also loses temperature quickly, I'm not convinced that warming them is the answer; but it may help. :confused:

Well, if your manager does think that (and, especially if it doesn't work) blame me!!!!!!!!!!!!! :D:D:D:D

Sorry to be contrary, but I don't think that the spin phase has much to do with it. I am much more convinced that it is the time when the reactants are mixed. Consider this. You have warmed both your reactants (presumably!) and your card; but have you warmed your pipette tips? The reactants are very small in volume (50uL and 25uL). When you draw these up into your tips, the surface area to volume ratio is very much in favour of the surface area. Therefore, the reactants are going to lose temperature extremely quickly. "Cold-reacting" antibodies tend to sensitise red cells extremely quickly (which is why setting up the tests at room temperature and then incubating them at 37oC causes so many problems); the k1 of the Law of Mass Action. But, dissociation between a "cold-reacting" antibody and its antigen happens relatively slowly, and probably does not happen within the incubation time; the k2 of the Law of Mass Action. Therefore, you get unwanted reactions. Using hand-held pipettes for the manual tube technique on the other hand, where larger volumes of both reactants are used, and larger volumes tend to be drawn up into a pipette that has a thicker bore, means that the surface area to volume ratio is nearer 50:50, and so there is a slower drop in temperature, and that may make all the difference. I may be talking complete rubbish, but it is something to think about. :confused::confused:

Wash your mouth out with soap and water. Gosh! :eek::eek:

Hear, hear. Mind you, I'm not so sure about the paragraph beginning, "As the saying goes..."; I've read some of yours!!!!!!!!!!!!!!!!!!!!!!!!! :devilish::devilish:

I thought your Lab was working well today!!!!!!!!!!! :devilish::devilish::devilish:

Sadly Marilyn, all of this does apply to us, which is probably why our inspections are so traumatic. :(

So he/she should have done. Well done!!!!!!!!!!! :D:D:D:D:D

My 10-year-old son has spent the day helping me make the mince pies and sausage rolls ready for Christmas. My kitchen now looks like an Operating Theatre does after a ruptured abdominal aortic aneurysm , except that you can substitute self-raising flour for the blood!!!!!!! :D:D:D:D:D:D:D:D

Perhaps you should have been more dogged with your validation with human plasma????????? :eek::eek::eek: Sorry, horrible pun, but it had to be made.

Yes, back some time ago, when the IRA bombed Harrods, I was working at Westminster Hospital (sadly, now closed). As you can imagine, it was a bit chaotic. We had a wonderful Senior Registrar in Haematology/Blood Bank by the name of Rollo Lewis, who took it upon himself to act as our "runner" and to also act as a conduit between Accident and Emergency and us in Blood Bank so that we were well aware of what was going on, how many victims we were dealing with, how many were in need of blood as an emergency, how many needed blood urgently and how many could wait. He also told us how the various victims were doing (e.g. if they moved from one category to another). I was the most senior person in the Lab that Saturday (a very basic grade technician) and I have never forgotten just how useful to me/us was the role adopted by Rollo. He made a huge difference, and I am certain that this (good communication) is the key in such situations. :):)

I agree entirely (especially, tongue in cheek, with the last bit)!. :D:D:D:D

Good Lord, if the Reference Service of the NHSBT in the UK could not/would not do cross-matching in really difficult cases, we would have Blood Bank Managers and Pathologists battering down the door to throttle us (actually, that's probably the only reason we do it - self preservation - ask Rashmi - she'd be first in line to string me up)!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :eek::eek::eek:

I agree with both the last two posts (well, not the termination bit, but the rest).

Fair comment Mary**, but what happens if there is an impasse (e.g. the Reference Laboratory says the units are suitable for the patient after cross-matching, but the Hospital Laboratory doesn't think they are suitable)? Is the transfusion not delayed unreasonably? :confused::confused:

I think that it is to do with the volume of cold blood and blood components that are transfused over a very short space of time bringing down the core temperature of the patient. This, in turn, leads to less efficient enzyme kinetics in things such as the clotting cascade (apart from other systems relying on enzymes) and the patient going into, effectively, hypothermia, on top of their trauma. I stress, I think! :confused:

I know of Hospital Laboratories that do this jcdayaz, but it is not as effective as washing tubes manually with pre-warmed saline. The reason I can say this with some certainty is because they will very often say that they have tried pre-warming the cards and got nowhere, before they send us the samples, but we find nothing by manual tube technique with warm-washing. Sorry! ;)

Much as I am loathed to say it, these are very good points! :tongue::tongue::tongue::tongue::tongue::tongue: