case study help

[NAN47]

Hi I am a BMS in Haematology and Blood Transfusion in the UK and i am currently studing for the higher specialist diploma in Transfusion science. I have been looking at last years past papers and one of the case studies has got me stumped. was looking for some advice as to how is best to tackle such a question. I am a little confused as I work in a district general hospital as opposed to a reference centre and I am not sure whether i should answer the question with what I would do in my post or look at it from the perspective of what the reference centre would do.

any help would be gratefully received!

Case Study 3.docx

[Malcolm Needs ☆]

Hi I am a BMS in Haematology and Blood Transfusion in the UK and i am currently studing for the higher specialist diploma in Transfusion science. I have been looking at last years past papers and one of the case studies has got me stumped. was looking for some advice as to how is best to tackle such a question. I am a little confused as I work in a district general hospital as opposed to a reference centre and I am not sure whether i should answer the question with what I would do in my post or look at it from the perspective of what the reference centre would do.

any help would be gratefully received!

Hi tricia47,

I know for a fact that there is another member who could answer your query better than me (no names, no pack drill), but I will do my best - however, it is now 21.00 hours, and I am on call tomorrow, so sleep comes first.

If the other member has not answered before me tomorrow, I will give it a whorl!

:):)

[NAN47]

thanks Malcolm!!!

[Fluffy agglutinates]

I am not sure whether i should answer the question with what I would do in my post or look at it from the perspective of what the reference centre would do.

any help would be gratefully received!

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.

[NAN47]

Hi there, thanks so much for your input! Yeah we do coombs and enzyme panels on our positive antibody screens, we also have the Diamed - ID panels which i would use to try and eliminate possible specificities. I also have an understanding of the principles of how enzyme techniques affect/destroy certain antigenic specificities ie M fya etc, also that i would expect to see the Rhesus specificities being enhanced by the enzyme technique. I would also look use the ruling out technique and looking at reaction pattern strength to aid my investigation. However when we have multiple possible antibodies which we couldnt confirm we would crossmatch units for compatibility and then send it to the reference centre for confirmation. also i would do an autologous control to help to identify whether there could be a possible auto-antibody present in anddition to alloantibodies

I have a basic understanding of adsorption and elution techniques ( however I actually havent performed them personally) and was wondering if that is the route that the reference centre would go down or if they have other panel in use to rule out and determine and antibodies which are being masked.

part of the question is which antibodies of clinical significance, if any cannot be excluded and which can be positively identified, am not sure how i would answer that without further investigation?

hope i am making sense!!

many thanks

ps i will give it a bash!!

Edited June 29, 2010 by tricia47

[Fluffy agglutinates]

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

[NAN47]

ok thanks, will give it a go and see how i get on. Think that my problem is that i often look at the more complex sides to things first, whilst ignoring the obvious!! will try to remember KISS!!

thanks:)

[Malcolm Needs ☆]

ok thanks, will give it a go and see how i get on. Think that my problem is that i often look at the more complex sides to things first, whilst ignoring the obvious!! will try to remember KISS!!

thanks:)

As the Reference Service Manager at Tooting, I can assure you that I use KISS all the time - but that may be because I really am stupid!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

:eek::eek:

[David Saikin]

It would be interesting to those of us "across the pond" to see this case study . . . for our own edification of course. Is that possible?

[Malcolm Needs ☆]

It would be interesting to those of us "across the pond" to see this case study . . . for our own edification of course. Is that possible?

Hi David,

tricia47 attached the case study in the first post of this thread.

All the best,

Malcolm

:):)

[Fluffy agglutinates]

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?!

[NAN47]

ok - have pondered and deliberated over this for long enough and whilst i may just be demonstrating the SS part of KISS, this is what I have come up with and I am not very confident about it!!

ok the antibodies which i have positively identified is anti-M reactive at 37c by IAT and depressed by enzyme as expected. Patients M- phenotype also confirms this.

Other antibody specificities which ? positively identified as according to BCSH guidelines for assigning specificity include; anti-C, anti-S, anti-Fya and anti-Jkb. I have excluded anti-Cw and Kpa due to the fact that they are rarely clinically significant and are often not expressed on antibody screening cells. ? anti-Le(a) as this would only require to be IAT cross-match compatible.

This process which I used for achieve this result is the 'crossing out' method and excluding specificities base on non-reactivity with the serum and this allowed tentative exclusion of antibodies to antigens expressed on non-reactive cells.

Additional test which i would perform would be to include an auto-control as a way of excluding an underlying auto-antibody. I would then use an additional panel ( Diamed ID) as a way of further excluding specificities ie would use a reagent cell which is R1R1 M- as a way of excluding anti-C ( would have expected this to have reacted by enzyme) . I would select reagent cells and sytematically try to eliminate each of the potential specificities present.

I would also crossmatch by IAT blood which is antigen negative for each of the probable antibodies present as a way of demonstrating comaptibility to the blood and providing additional confirmation of antibody specificity.

I really feel that this is not correct but have been racking my brains and it is the best i can come up with!!

thanks

tricia

? also deliberated the point of a room temperature panel???

Edited June 29, 2010 by tricia47

[BSIPHERD]

ok - have pondered and deliberated over this for long enough and whilst i may just be demonstrating the SS part of KISS, this is what I have come up with and I am not very confident about it!!

ok the antibodies which i have positively identified is anti-M reactive at 37c by IAT and depressed by enzyme as expected. Patients M- phenotype also confirms this.

Other antibody specificities which ? positively identified as according to BCSH guidelines for assigning specificity include; anti-C, anti-S, anti-Fya and anti-Jkb. I have excluded anti-Cw and Kpa due to the fact that they are rarely clinically significant and are often not expressed on antibody screening cells. ? anti-Le(a) as this would only require to be IAT cross-match compatible.

This process which I used for achieve this result is the 'crossing out' method and excluding specificities base on non-reactivity with the serum and this allowed tentative exclusion of antibodies to antigens expressed on non-reactive cells.

Additional test which i would perform would be to include an auto-control as a way of excluding an underlying auto-antibody. I would then use an additional panel ( Diamed ID) as a way of further excluding specificities ie would use a reagent cell which is R1R1 M- as a way of excluding anti-C ( would have expected this to have reacted by enzyme) . I would select reagent cells and sytematically try to eliminate each of the potential specificities present.

I would also crossmatch by IAT blood which is antigen negative for each of the probable antibodies present as a way of demonstrating comaptibility to the blood and providing additional confirmation of antibody specificity.

I really feel that this is not correct but have been racking my brains and it is the best i can come up with!!

thanks

tricia

? also deliberated the point of a room temperature panel???

I suggest you go back and review the enzyme panel. Remember all of the cells run by enzyme technique were negative. So you can use them to rule out antibodies to antigens that are not destroyed by enzymes (many of those are actually enhanced by enzyme treatment).

[David Saikin]

Thanks Malcolm

ds

[Fluffy agglutinates]

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!

[NAN47]

thanks for that, that was really helpful,

I am hoping to get over to our local reference centre in August for a few days, to see more on Special Investigations etc. In the course of my studying I am realising what a vast subject area blood transfusion is, but also very interesting!!

thanks again, am sure that i will have lots more to ask!!

[BSIPHERD]

I assumed the Enzyme panel was Coombs phase. Since that may not be true, I would take the enzyme panel through the IgG phase.

[Fluffy agglutinates]

I assumed the Enzyme panel was Coombs phase. Since that may not be true, I would take the enzyme panel through the IgG phase.

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!

[Malcolm Needs ☆]

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!

Yippee! I would have got a bonus point!!!!!!!!!!!!!!

:D:D:D:D

[Fluffy agglutinates]

I am hoping to get over to our local reference centre in August for a few days, to see more on Special Investigations etc. In the course of my studying I am realising what a vast subject area blood transfusion is, but also very interesting!!

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!