Malcolm Needs

One of my all time favourites was given to me by one of my mentors, Joyce Poole. She, in turn, got it from the late, great Eleanor Lloyd, who was the first Biomedical Scientist (Technician) to be given the honour of being made the President of the British Blood Transfusion Society. It was a very simple, but profound piece of advice about the world of Blood Transfusion. It was; "Enjoy, enjoy!" It is a piece of advice that I have taken to heart for the past 37 years, and have found it to be incredibly useful and easy to follow. I hope you all, also, find it useful. :D:D:D:D

Oh Lara, you are sooooooooooooo passe! These days you should be using *****-driver and screws; preferably a Phillips!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! You get far longer lasting and stronger agglutination. :D:D:D:D

I really do wish I could, but it is a technique used, I think, exclusively by some of the hospitals my Reference Laboratory serves (in particular, by those hospitals in the east of the county), and one that we have yet to master ourselves! I sometimes fell that we are unworthy of performing tests for those in my mind, because we can rarely find these "antibodies" that they, apparently, can regularly detect! On Saturday, for example [and just in case Rashmi gets even more paranoid, it wasn't her Laboratory] I had a sample in on a patient with a GI bleed. DAT+ 4+ IgG only and a panagglutinin true, but free auto-antibody in the plasma gave results far <1+ [one or two cells making love to each other, whilst the vast majority were being wall-flowers] and I had to hold their hands and cross-match for them, whilst the patient had to wait about 4 hours for their transfusion [given the time it took for the sample to get to me, me to test it, me to cross-match it, and then to get the blood back to the hospital. I am still really worried that I could not find this auto-antibody, just in case...... The patient is fine, by the way!!!!!!!!! :D:D:D:D:D

One of ours for new staff members was sending them down to stores for a box of fallopian tubes. :eek::redface::eek:

splendid!!!!!!!!!!!!!!!!!!!!!!!!!!! :d:d:d:d

I think I'll try this. Then I can get them for having food in the Laboratory too!!!!!!!!!!!!!! :devilish::devilish::haha::haha:

The only thing that you can do in such a situation (unless, of course, there is a history of atypical alloantibodies detected in the Mother's plasma during the pregnancy) is make an eluate from the baby's red cells to ascertain what specificity/specificities is/are causing the positive DAT, and then give group O, ABO high titre negative blood, suitable for exchange transfusion, that is also negative for the implicated antigen/antigens. Good luck!!!!!!!!!!!! :eek::eek:

A very fair comment Lara. I stand corrected and you are completely right in what you say. :):redface::)

Well, that's not quite true Lara; it is just the case in the overwhelming number of newborns. You do come across the rare newborn that has an ABO antibody that could not possibly have come from the mother (e.g. mother AB, baby A, with an anti- - but they are very rare. :redface:

Yes, you can find it (and other really useful information) in; Daniels G, Poole J, de Silva M, Callaghan T, MacLennan S, Smith N. The clinical significance of blood group antibodies. Transfusion Medicine 2002; 12: 287-295. :D:D

I see absolutely no reason why not, but, knowing that plastic takes longer than glass to heat up, and the air inside them would also need to heat, as there would be little circulation, how about keeping a supply of tips in the incubator at all times, so that they are already heated to the desired temperature. :confused:

Not that I can see. The reason that she is not making an anti-A is that she is probably a secretor, and will still be secreting A substance. Therefore, either her "new" immune system is tollerant of the A antigen, or her A substance is inhibiting any anti-A that is being produced by her "new" immune system.

I would tend to agree, but would be much happier giving group A, rather than group O blood, because there are a higher number of H antigens exposed on the group O blood. :confused:

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: