Fluffy agglutinates

Ok so back on topic! Just had a chat with the reference lab about positive DATs causing problems with D grouping when using Ortho, they say they see these referrals on a regular basis. Referred either as 'D??' or changed from 'historical D- to D+' this time. Usually most turn out to have a positive DAT & are actually D-. Worth a try doing a DAT to see if it will help resolve the situation, especially since your tube group was D-.

My apologies oh master of transfusion terminology! Please spare the rod this time...

I guess I'd better not make any comment on your other post about you being THE original A1 then...

We did have a case once where a patient appeared to produce a cracking anti-K (titre at least 1/1024) after transfusion of K- units. The hospital lab was most annoyed to find out that it had come from the donor! Also made reporting the antibody status on the patient history very tricky... Of course this anti-K only reacted in IAT so wasn't detected by the donor testing lab.

I make it a general rule to be highly suspicious of anyone selling me anything!!!

If you're using ortho gel technology I have heard that a positive DAT can sometimes affect the D typing! Does the patient have a pos DAT?

It will depend on several factors: For neonates the donation must be antibody screen neg by IAT For donations intended for adults in the UK the antibody screen is done by enzymes using a 2 cell pool covering D, C, E , c, e & K. The following rules are then applied: Pos on neat screen - all products ok for adult use Red cells in SAG-M can be used with a pos screen at a dilution of up to 1 in 50. All other products have a dilution limit set at 1 in 10 (i.e. if screen is pos the product is discarded or used as a reagent). The reasoning behind this is; within a given donation there is a finite amount of antibody present. When transfused to an adult this will be diluted by their blood volume & not have any effect. There is also evidence to show that the only antibodies likely to affect an adult will be strong examples of Rh & K. So in the UK we do not do an IAT screen unless the donation is intended for paediatric use. In a small volume person - neonate - the dilution factor does not exist & all clinically significant antibodies could potentially cause harm. Therefore an IAT screen is essential. Does your blood service perform an IAT screen on all donations as standard?

Absolutely spot on LisaM! The paper reference is: The Duffy blood groups of Jarawas - the primitive and vanishing tribe of Andaman and Nicobar Islands of India. M.K. Das et al. Transfusion Medicine, 2005, 15, 237-240. I just wish that they had gone on to do molecular work too, this would have shown whether their mutation is carried on FYA or FYB. This could then possibly show that both mutations actually originated in Africa aroound the same time. I would also like to know if there has been any Duffy typing done on the Australian aborigine population. So far I haven't been able to find any published work. I find Duffy fascinating when used as an ancestral marker. Your turn for a new question I do believe...!

That is an excellent idea, they're very friendly people & like to show you as much as they can. Who knows you may get to meet the infamous Malcolm! Where's your local? Glad you're enjoying the learning, I think it's a fascinating subject - always more to know!

I really appreciate your posting. In the UK, at the moment, most hospital labs do their enzymes without AHG - this may change but for the time-being unless the panel states 'ENZ IAT' we are taught to assume the technique used was 'plain enzymes'. It is confusing, especially when you're trying to teach this stuff & also when most of our reference labs have now switched to 'ENZ IAT'! As an answer to an exam question anyone mentioning ENZ IAT & excluding Kidd antibodies would get a bonus point from me!

I think you've made a great first attempt! To stick with the basics first: I would agree with the positive identification of anti-M. I think you need to be more careful with your terminology - do not say '? positively identified' as this doesn't really make sense. So instead use for example 'the following antibodies are masked by the anti-M/ cannot be excluded by this set of results'. Because the anti-M has only left you with 2 negative reactions it is impossible to exclude anti-S, anti-Fya, anti-Jkb, anti-Lea. In addition to this anti-C is masked in IAT. Some people would use the enzyme results to say anti-C is excluded (some would need to see this in IAT also), this is debatable & for this reason it should be mentioned in your answer (like you did)- if your lab protocol is to exclude all antibodies by IAT then say so (also check this agrees with current guidelines!) The patient phenotype only helps you realise that this patient could actually make all of these masked specificities & therefore further work must be done. You've mentioned the R1R1 M- cell which is great - now you need to do the same for all the others - I would expect them to be listed in your answer if I was marking this. Take care when citing your reasons for 'excluding'. Excluding means you looked for it & KNOW it isn't present. Therefore you cannot say you have excluded anti-Cw or anti-Kpa or anti-Lea. Crossmatching for each of the probable antibodies is a big no-no & is quite frankly a waste of your own time - this is why we have panels. Crossmatching is not the best way of picking up antibodies. Besides you would need to acquire donor units which matched all the negatives. The best way to exclude is by using reagent cells. RT panel - you would only do this if you suspected a RT optimal antibody that wasn't clearly there by IAT. I'm sure I've missed some points along the way... Please feel free to ask more etc!

Now that's just mean!!

I always remember a saying once told to me (although I can't for the life of me remember who that person was!) If you hear the sound of hooves expect HORSES not ZEBRAS! Apply this thinking to your serology results. Obviously this applies in the UK I guess in Africa it would be the other way round... Of course we mustn't forget Sherlock Holmes! Eliminate all other factors, and the one which remains must be the truth (one of the many variations of similar quotes). Can we rename ourselves as antibody detectives?!

No problem, happy to help! It sounds like you have a good solid understanding of antibody id principles & practice. People tend to get unnecessarily bogged down in adsorption/ elution techniques where they don't apply & in this case they don't! In the reference lab we try the KISS (keep it simple stupid - not meaning to be rude to you of course!) principle as far as possible. Ref labs do not adsorb & elute everything. We wait & see what the results are telling us first & then decide on next steps. These results are telling me I don't need to adsorb. Ref labs generally have 4/5/6 different panels available to use (as well as an assortment of rarer cells if needed) As I said I don't want to give you the answers first so you need to work out why you wouldn't need to do an adsorption in this case (remember to KISS!). What are you going to use to exclude any masked antibody in this case? What they are asking for is for you to explain what tests you need to put up next & what the outcome may be. What do the BCSH guidelines tell you about positively identifying an antibody specificity? (clue: see section 7.7.2! Table 1 lists clinical significance) http://www.bcshguidelines.com/pdf/transfustionlabs.pdf

Saw this baby at the BBTS conference last year & was amazed by it! http://diamedil.info/info/IH_1000__Presentation.pps#258,1,Welcome to the Future Most of the automated machines in use currently in the UK do have heated blocks which the cards sit in (either at 37 or 22oC). Main problem is the samples & reagents are 'cold' - so can't do a true prewarm by automation.

Hi there, Malcolm has given me a heads up to lend a hand. I haven't been trawling this forum for a few days so I missed your post. I currently set the questions for the BBTS specialist exam in transfusion science practice so from that perspective I can tell you what we'd be looking for... The answer is never 'send it to a reference lab' even if that is what you would do. Anyone can parcel up a sample & wait for results to come back. You are required to understand & explain what would be done even if you do not currently do this yourself (when you pass this qualification it will demonstrate that you have some of the skills required for working in a reference lab). So in this case study they are looking at your understanding of antibody identification. Not just what that antibody is but also: How is it reacting? by what techniques? how is it not reacting? How did you come to your conclusion? How did you rule-out other antibodies? Do you understand what is meant by 'masking'? Is this different from 'cannot be excluded'? How do you demonstrate that there is/ isn't another antibody 'hiding'? What guidelines help you with this process? Is this antibody clinically significant? How confidant are you in your antibody identification skills? Out of interest do you have much experience doing panels or are all your 'screen positives' sent away? I don't want to give you answers without seeing what you can do first, so why not have a crack at answering the case & posting your results? If you're shy then send me a PM through the forum & no one else will see! More than happy to help. I'm sure Malcolm & others on here will also be very helpful & will jump-in with suggestions too.

That it has never been produced by a human! And I think that is still the case. Now if I have that correct, sticking with Fy, my question is... Which ancient tribe of people (still in existence but only just!) with a high proportion phenotyping as Fy(a-b-) are thought to have originated out of Africa ~60,000 years a go & be the ancestors of the indigenous Papua New Guineans & Australian aborigines? Clue: they inhabit a group of islands between Africa & PNG!!

This is where the package insert needs to be read most carefully - most of the products in use currently have specific instruction on how to use in cases for IM or IV (& if not suitable for IV will say so!). The major product in the UK at the moment is... Rhophylac ® Rh0(D) Immune Globulin Intravenous (Human) 1500 IU (300 mcg) For Intravenous or Intramuscular Injection Initial US Approval: 2004 I think for the US it's RhoGAM? (that insert handily instructs you not to inject the newborn baby!)

In the UK large doses are 'encouraged' to be given IV rather than IM. It also means you don't have to give as much & the mother doesn't have a throbbing shoulder! There is also discussion taking place over the benefits of the 28 week prophylaxis dose being given IV instead of IM.

Have a look at the traqprogram here... http://www.traqprogram.ca/products.asp The manuals are excellent, can be easily adjusted to your own procedures & simple too!

Ok I give up! Its just that I'm suspicious of the existence of anti-Fy5 & was wondering how many people have ever seen one - an internet forum seemed like a good place to ask! There isn't enough available info on the antigen or antibody to satisfy me! I really want to know where/ what the Fy5 antigen is...

Always worth asking about ethnicity - I would be surprised too though! (I wonder if we'll ever see a homozygous 'Brazilian FY null type' that will produce anti-Fy3 and/ or Fy5?) Do you happen to remember how old the human stuff was? When confirming a patient has anti-Fy3 do you rule-out anti-Fy5?

I would love to know how many of you have come across anti-Fy5 over the years? If so how did it react; what problems did you have; & when was it originally discovered/ identified as anti-Fy5? Also, if possible, the ethnicity of the patient would be interesting. Thank you!

If you sit & have a think about this for a while you will see that this is how an autoantibody begins to show itself! If you were to make an autoantibody where would it attach itself to first? Your own red cells = pos DAT! (IgG coated) You peform an elution & you reveal the autoantibody. If you hadn't made a lot of autoantibody yet it will be completely 'mopped' up by your own cells = negative antibody screen & panel. In my personal experience most autoantibodies do not show a specificity & the elution shows panagglutination. However I have seen exactly what you are describing a number of times - it is not that unusual. It would be interesting to follow your patient over the next few months to see if the autoantibody increases to the point where it starts to appear in the panel & eventually reacts with all cells. Alternatively it may stay as it is & not get any worse. Hope that helps a bit! (If you wish to read up on the subject try the AABB technical manual)

I too would like to know why you would wish to do this. I believe that once C3d is bound to a red cell there is no way of removing it. As for C3b it is very labile & is almost immediately converted to an inactive form. What problems are you having that removing the C3d might help you? I can only think of antigen typing if you are using an AHG step? In which case use anti-IgG instead of AHG. If you let us know the problem we may be able to help you better.