Malcolm Needs

Hi John, Don't forget that I am the manager of a Red Cell Reference Laboratory that covers about 50 hospitals, including at least three large London Teaching Hospitals. This explains the high numbers of panels we perform. This number includes are "number one" panel (as it were), and then panels that are almost all R1R1 and panels that are almost all R2R2, so this boosts our numbers quite a bit. We don't actually have 50 to 60 referred samples a day (thank goodness!). The answer to your question really depends upon what techniques your local ARC use themselves. As you may have seen in other threads, the gel technique is very sensitive, but is not necessarily as specific as some other techniques. Last night, for example, I dealt with a sample that had a pan-reactive auto-antibody in it reacting by gel enzyme technique (5+). By gel IAT, there was quite clearly an auto-anti-C present (or possibly an auto-anti-Ce, but, hey, who cares at 2 o'clock in the morning, when the exact specificity makes no difference to the treatment of the patient?) and a few scruffy 1+ reactions with some of the other cells in the panel. By pre-warm, warm-washed LISS tube IAT, using a monospecific anti-IgG reagent, however, there was no evidence of any reactions whatsoever (and yes, I did do all the necessary controls using a weak anti-K, anti-Fya and anti-c for comparison, and adding IgG-coated red cells to the negative tubes, to all those who disparage this technique), so if your ARC does something similar, this could explain the situation. As to antibodies you are picking up by one technique, but not another, as I have said in other posts, this is of no surprise at all, as these antibodies are derived from humans of course (as opposed to grouping reagents that are usually monoclonal nowadays) and the variable regions of these antibodies will react in different ways in different techniques (slight changes in amino acid residues in the variable region, and the constant regions come to that could explain these variations in reactivity, as does the subclass of IgG being detected by the reagent AHG). Not all antibodies will react by all techniques. We detected an anti-S by LISS tube IAT a few years ago when I was working in a hospital Blood Bank that was sent around to quite a few different hospitals and the Reference Laboratory where I now work, and this anti-S was only ever picked up by tube technique. I tend not to worry about antibodies that react only by gel IAt or by solid phase IAT, simply because these techniques are very, very sensitive, and the reactions in gel or solid phase are usually very, very weak (although, conversely, I would recommend antigen negative blood for the patient). On the other hand, I do worry about tube only antibodies, unless they too are very weak. I hope that these vague ramblings answer some of your questions, but if not, get back to me and I'll give it another go! :)

Hi Cassie, If it were an auto-anti-e, there is a fairly good chance that it would actually be an auto-anti-e-like mimicking antibody. In this case, there would also be a very good chance that this "anti-e" could be adsorbed to extinction by R2R2 red cells. If it were a genuine allo-anti-e, this would not happen. With reference to the compatible donor, of interest would be the ethnic origin of the patient in this case, but also of the donor. There is always the chance that the donor had a variant of the Rhe antigen; more so if he or she were of Black ethnic origin. :confused::confused:.

I agree that you most certainly would if you were using the tube technique as the "only line of attack", but if you are using it in conjunction with Provue, and always wait for the Provue results before issuing the blood, then you are using the tube technique as nothing more than a screen (and an aide to putting up units of the correct group at the same time as performing the Provue group and screen) and, therefore, the need for controls each time is negated. Mind you, what happens when there is a discrepancy between the two (tube group and Provue group) would be interesting!

I agree with everything you say here adiescast, but I think it is well for everyone to remember that there are certain antibodies that will always react more strongly by method, rather than another, or even some that only react using a particular method, and so correlation will never be exact for all antibodies. We find that we detect an awful lot of anti-M's by gel, partly because of the fact that we are (usually) mixing the reactants at room temperature prior to incubation at 37oc, thus allowing sensitization by a "cold" anti-M prior to incubation, and partly because, if I remember TimOz's post correctly, the pH of or in the gel is slightly lower than that of the phosphate buffered saline and LISS we use for tubes. We notice a rise in titre of about one dilution when we went to gel, but we also sent out a circular to all the hospital Blood Banks and the hospital Obstetric Units prior to "go live" day, to warn them of this expected change. They were quite happy about it and (for once!) took notice.

Thanks for that. Well, I survived! I had another DAT positive sample in after I wrote that post and was actually in the lab for 10 hours from 17.00 to 03.03. Boy, was I craving for the coffee by the end! Now, all we have to do is wait and see if the patients survived my cross-matching! :rolleyes:

Ah, don't get me wrong John. I actually like the gel technique, and we use it as a first line of attack for most of our samples. It's only when we are dealing with auto-immune samples (about 5 a day) that we use the LISS tube technique. We're performing something like 50 to 60 antibody panels a day, and it is much quicker to perform these in gel, but there is quite definitely a place for the LISS tube technique.

Cheek! Coming from someone who admits to having five hundred 21st birthdays!

Don't worry Rashmi, you're stuck with me being around for a few years yet!!!!!!!!! :D:D:D:D

I'd go along with that, but the wait for the Provue results is absolutely vital if you don't control your tubes.

Hi John, Thanks for that. I'll probably have to do this early next week, as I'm on-call tonight (Friday) and Sunday. Had a good start too. A group O patient with anti-V, anti-VS, anti-N, anti-S, anti-Lua, anti-Jsa, anti-Fya and anti-Fy3, (who also requires HbS- blood as she is a sickler) with an Hb of 4g/dL, and another MDS patient with mixed warm and cold auto-antibodies who requires a cross-match. I wonder why these people can ONLY require a cross-match on a Friday night!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! And to cap it all, it so hot here that the milk for my coffee has curdled.

Yes, it is extremely scary! We usually recommend not transfusing if at all possible, but if it is deemed necessary, using IVIG and methylprenisolone cover. This seems to help.

I'm sorry shily, but to say that gel technology is safer than the LISS tube IAT is totally untrue. AMcCord is absolutely correct in saying that it may be more sensitive, but you lose specificity. If the LISS tube IAT is so dangerous, do you think that it would be the first line of attack at the International Blood Group Reference Laboratory and would have been used by such luminaries as Dr. Carolyn Giles, Dr. Elizabeth (Jan) Ikin, Dr. Kenneth Goldsmith, Dr. Robert Race, Dr. Ruth Sanger, Dr. Arthur Mourant, to name but a few, and do you think it would still be used by people such as Joyce Poole? :mad::mad::mad:

True, it shouldn't really matter, but when the inspector demonstrates that they do not have even rudimentary knowledge of what the laboratory does, but still insists on changes being made to fundamental processes, with no demonstrable improvement (and change should only be made if it can be measured), it most certainly does matter.

IN the UK, the BCSH Guidelines for compatibility procedures (2004) state: "It is essential that the request form and sample contain the following minimum patient identification (PIN) as described in BCSH Guidelines for the administration of blood and blood components and management of transfused patients (BCSH, 1999). (i) surname/family name (correctly spelt); (ii) first name(s) in full; (iii) date of birth (not age or year of birth); (iv) hospital number/accident and emergency number/NHS number/major incident number (in certain instances, such as a male partner of a pregnant lady, we will also accept an abbreviated address as an identifier, if none of the other criteria listed in iv are available - MN). The sample should be dated, labelled and signed by the person taking it. The request form should also include the patient's location and the location where blood units should be sent and the signature of the person making the request.... Provided that sample labels are printed and attached to the bottle next to the patient at the time of phlebotomy, hand-held bedside/chair-side scanners and printers utilizing bar-coded wristbands may increase security during phlebotomy. Labels produced in this way are not the same as addressograph labels, which are more likely to result in inadequate checking of PIN at the bedside (Sharp and Cummings, 2001). It is therefore recommended that any labels preprinted away from the bedside should not be accepted for either grouping or pretransfusion testing samples.... Samples received from trauma or unconcious accident and emergency patients are unlikely to contain the full PIN. There, however, must be at least one unique identifier, usually an accident and emergency or trauma number, and the sex of the patient identified on the sample label. The sample should be taken andlabelled and the form and sample should be signed by the prescribing medical officer as one continuous procedure. In the event of there not being at least one unique identifier on the sample in a life-threatening situation, group O blood only must be issued until a suitably labelled sample is available. If the patient is a female under 60 years old, group O D-negative blood should be given." When I was working in a hospital, we stuck rigidly to this guideline. Now I am working in a Reference Laboratory, many miles from some of our referring hospitals, and where it may be difficult to obtain replacement samples (particularly in an emergency), we may have to work on the samples under a concession form, if the mis-labelling is minor, signed either by one of our own Consultants or, in certain cases, me (as the Reference Service Manager). As all of our samples come through the hospital Blood Banks before referral to us, it is surprising how many we have to reject, or have to work on under concession! :rolleyes:

It isn't for the MHRA either. Almost all of them come from the pharmasuitcal industry. WIth the CPA, it is slightly better, in that they tend to be Biomedical/Clinical Scientists or Consultants, but, they don't necessarily have had to have worked in Blood Transfusion or even Haematology. :mad::mad::mad:

That's terribly cynical SMW, and I agree entirely with everything you say!!!!!!!!!

Oh John, I do apologise, but I'm going to have to disagree again! Anti-D was most certainly the first antibody studied for HDN, but it is by no means the only antibody to have been studied. Anti-c has also been studied extensively. Over here, for these two antibodies we do not perform titrations, but rather we perform quantification. All below assumes that the baby's red cells express the antigen (otherwise, of course, it would be nonsense). For anti-D, if the level is below 4IU/mL, there is little chance (not no chance, but little chance) of an affected baby. Between 4 and about 15IU/mL there is a moderate chance of an affected baby. Between 15 and 20IU/mL, there is a high chance of an affected baby. Over 20IU/mL, there is an almost certain chance of hydrops, unless there is intervention. For anti-c, up to 7.5IU/mL, there is little chance (once again, not no chance, but little chance) of an affected baby. Between 7.5IU/mL and 20IU/mL, there is a moderate chance of an affected baby. Over 20IU/mL, there is an almost certain chance of hydrops, unless there is intervention. We titrate all other antibodies, and are not really worried, unlesws the titre reaches well over 32, but in the case of anti-K and anti-k, we know that the antibody titre does not have to reach these stellar titres before severe HDNF can occur, because the Kell antigens are expressed extremely early on the red cell precursors in the bone marrow (much earlier than the Rh antigens). There are other antibodies that have been studied though (not least what used to be called anti-Tja, which caused recurrent spontanious abortions in the first trimester). Sorry John. :redface::redface:

It's because, if the unit is infected, the parents won't lose both twins or all three triplets.

I agree with you L106; performing a DAT on all cord samples is extremely excessive. You are quite right that, if anti-Fya is eluted (as long as the last wash control is negative) then there is no need to treat the baby's red cells and then group them. But I really agree with you wholeheartedly about the fact that I can't spell! :D

Hi Chun-kwok, I think there can be no better explanation than to quote directly from Geoff Daniels book, Human Blood Groups 2nd edition, 2002, Blackwell Science, "Abantu is another variation of Aend, found in about 4% of group A black South Africans (paper 245 cited), and in up to 8% of Bushmen and Hottentots, the ethnic group in which the Abantu gene may have originated (paper 301 cited). Anti-A agglutinate Abantu red cells more strongly than Aend cells." Paper 245 is, Brain P. Subgroups of A in the South African Bantu. Vox Sang 1966; 11: 686-698. Paper 301 is, Jenkins T. Blood group Abantu population and family studies. Vox Sang 1974; 26: 537-550.

Welcome Andy. Love the quote about the rings (but I don't think I'll pass it on to my wife - it could be very painful indeed!).

Hi Jeanne, I am not sure to which paper you allude, as there have been several that have come out of the UK on this subject (many by my own Consultant, Dr. Nay Win). The possible mechanism for IVIG (and steroids) is discussed in some detail in: Win N, New H, Lee E, de la Fuente J. Hyperhemolysis syndrome in sickle cell disease: case report (recurrent episode) and literature review. Transfusion 2008; 48: 1231-1238. I hope this is of help.

Then, on this point John, we must agree to disagree, but the thread has certainly brought about some lively discussion and identified the fact that there are (at least) two schools of thought on the subject, with each school adhering to their own ideas on the subject in an equally rigorous manner.

I agree with (almost) everything you say here Mabel. The only slight disagreement I might have with you is in the predictive nature of any anti-A that might be eluted. Whilst I would totally agree with you that titration of IgG anti-A (or anti-B come to that) is a waste of reagents, time and money, if the index neonate is affected in any way by the maternal IgG anti-A (albeit subclinically), the next and subsequent group A babies borne by the same mum will be affected at least as much as the first, if not more so, and at the same gestation period or earlier, so its demonstration does alert the neonatologist to watch for potential problems in future pregnancies. I also agree that the DAT due to ABO IgG antibodies can often be negative at birth, but equally as often, the DAT becomes positive after a couple of days. To "get ahead of the game", so to speak, it is sometimes worthwhile putting the cord sample in a fridge for a couple of hours and then examining it macroscopically for agglutination. IgG ABO antibodies can cause agglutination, and this agglutination is sure as hell not going to be caused by a "normal" maternal "cold" agglutinin, such as anti-I, anti-HI, etc. Just a thought.

Which one wil sort it out Rashmi? A single system or you retiring (remeber, you've just had yet another birthday???????????!!!!!!!!!!!!!!!!!!!!!!!!!!!!! SORRY; COULDN'T RESIST IT (BUT SHOULD HAVE DONE)!!!!!!!!!!!!!! :rolleyes::rolleyes: