jmm8427

One could argue that by doing the panel first you are being efficient and potentially saving time with antibody identification if something is detected.  But by doing the screen you are saving reagent/cost.  I'm not sure there is a right or wrong answer to this question?

It sounds like if at that point (after throwing everything at it including DTT and papain) you don't have the rare antisera/cells and reagents to identify the antibody then you are going to have to send it out anyways and the reference lab will probably end up repeating most of that testing in order to ID the reactivity on their end.  You are right, you have to consider that implementing trypsin is a big project with SOP revisions, may involve added costs, is known to have stability issues, and how often do you expect you will really need it and keep your staff competent?  Will it really have any added benefit to your testing?  
From personal experience in a smaller reference lab with limited rare reagents as well as in a larger IRL, I would say it sounds like you may want to wait on the trypsin until you have a better inventory of rare reagents to aid in completing antibody ID?   

It sounds like if at that point (after throwing everything at it including DTT and papain) you don't have the rare antisera/cells and reagents to identify the antibody then you are going to have to send it out anyways and the reference lab will probably end up repeating most of that testing in order to ID the reactivity on their end.  You are right, you have to consider that implementing trypsin is a big project with SOP revisions, may involve added costs, is known to have stability issues, and how often do you expect you will really need it and keep your staff competent?  Will it really have any added benefit to your testing?  
From personal experience in a smaller reference lab with limited rare reagents as well as in a larger IRL, I would say it sounds like you may want to wait on the trypsin until you have a better inventory of rare reagents to aid in completing antibody ID?   

One could argue that by doing the panel first you are being efficient and potentially saving time with antibody identification if something is detected.  But by doing the screen you are saving reagent/cost.  I'm not sure there is a right or wrong answer to this question?

Curious as to the benefits vs. the time it takes to prepare, validate and store these enzyme stock solutions (alpha-chy, pronase and trypsin)? 
Currently at a reference lab that would likely send antibody to high-incidence antigen workups out as we don't have much access to rare antisera and cells at the moment.  However, before we send it out (or while it's being worked up), we would like to at least try a narrow down the classification of the antibody and also perform enzyme and/or DTT treatment on pheno-similar cells, or adsorb out the antibody, to investigate any underlying allo to common antigens.  This way we can at least provide the hospital with a preliminary report of the patient phenotype and a potential aby to high-incidence antigen and any ID'd underlying aby.  
Eventually, when we build up our rare antisera inventory, we'd like to perform these IDs in-house.  For now, do you think DTT and papain are sufficient enough since we are sending these workups out anyways?  Looking at a few enzyme/chemical reactions on high-prevalence antigen charts and, other than -Yta, trypsin doesn't seem to determine any of these abys.
 

One could argue that by doing the panel first you are being efficient and potentially saving time with antibody identification if something is detected.  But by doing the screen you are saving reagent/cost.  I'm not sure there is a right or wrong answer to this question?

I agree, my experience with trypsin is not good either.  It took us quite a few tries to get it correct - the stability was the biggest issue.  It took lots of time to figure that out

Why do I get the distinct feeling that someone is not giving you the full picture on this one....???

Preparation and standardization of enzymes is notoriously VERY difficult (making trypsin is a nightmare). Each batch of source material may have a very different activity level than the previous. Stability is also an issue, even when frozen.
You can probably get all of the enzymes you list from Sigma, but they will undoubtedly have 15 versions of each and it may be difficult to choose which flavor is most suitable.
I would stick with papain and DTT. They'll be most useful, most often. You'll get a lot of information from just those two. Only the very highest-level Reference Labs. should mess with alpha-chymotrypsin, trypsin and pronase.

I wish!
Sadly no!

I totally agree!  And, from personal experience, finding the people with this deeper knowledge of blood groups is getting harder and harder to find...  Are you looking for a position in KY by any chance?  

Agreed jmm8427, but my point really was that, as far as I have seen from other job positions advertised on this site, the SBB exam is required for many of them.  However, I would have thought, from my own experience of having run one of the NHSBT Reference Laboratories for many years, that an greater in-depth knowledge of blood groups and blood group antibodies than that of the average person within the world of transfusion science, is a sine qua non, not least because the whole raison d'etre of a Reference Laboratory is to determine the specificity of an antibody or a mixture of antibodies, and/or to determine antigenic specificity, when the hospital laboratory is, at best, unsure.
I agree that there is a level within an organisation where a thorough knowledge of management, etc is of paramount importance, but I would have thought that, for someone who is going to be in charge of a Reference Laboratory, there is, of course, a need for managerial knowledge, but also for a much deeper than normal knowledge of blood group antigens and antibodies.

Hi! I'm Beth, and I'm a newbie Blood Bank Technical Specialist. I heard this was a pretty happening place to get the dish on all things Blood Bank! haha. I will have many questions... so there's your warning  I welcome all input, advice, words of wisdom. Feel free to help a sister out! Have a great day!

I think the manual we have asks us to replace them on a regular basis (every 2yrs? I don't have it in front of me), we do not validate (or re-validate) after replacing

You may be referring to trypsin-treatment of the red cells (screening cells). Apparently CD38 is destroyed/inactivated (along with Lutheran system determinants) but Kell system antigens remain intact. Other blood group antigens are also affected by trypsin, so I think the modified approach involves testing the patients' samples against both DTT-treated and trypsin-treated cells.
To further complicate matters.....manufacturing a reliable, consistent trypsin reagent is VERY difficult. The enzyme activity of source material varies immensely and, as with other enzymes, stability is a problem.

I haven't heard anything (but then I am retired), but something could come out from the ISBT Meeting taking place in Copenhagen at the moment.  I will get my "spies" on to it!

If pi is rounded to 4 decimal places that is.
 
Scott

Thank you for speaking Malcolm! It was a pleasure to see you and the entire SCABB conference was excellent!

Well, I had a simply wonderful time, thanks to Candy Williams and her colleagues.  Thank you for inviting me Candy.
 
I met some great people, including Marilyn Moulds (whom I "married", as you will see if I can manage to upload the photograph), Dr. Lawrence Petz (who was gracious enough to sign my copy of his book, coauthored with the late, and much lamented George Garrattyy, Immune Hemolytic Anemias) and Lara Thetford (LaraT23), for whom I have a huge amount of respect for the wisdom of her posts.
 
To say I am jet lagged is the understatement of the year, but WOW!!!!!!!!!!!!!!

A bit of a rant -- I'm surprised no one else has posted about this yet -- our last batch of screen cells from Immucor had a Wra+ cell and we have been PLAGUED with nuisance positives as a result. Called and complained and they sent us two sets, but we went through those already. They only have four days left on them so we're just sucking it up and trying to run everything we can on Echo (even more than usual, I try to run pairs and this month I've run a lot of single samples to avoid delays from a possible anti-Wra!). We found 4 in three shifts after opening them which was what prompted us to call. Who knew how common anti-Wra was (or wanted to know?!)    If it happens again I think we'll insist on the whole lot being replaced. We generally run traumas on the bench and had quite a few with anti-Wras, the docs tend to get nervous when the screen is positive and we're still ruling out majors!

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We recommend matching the Rh system (CcEe) and K, hemoglobin S negative units; matching Duffy, Kidd, MNS system only if they make an antibody.  (If it becomes too difficult to match exactly we do the best we can, we also attempt to molecular type them and confirm if the patient has the GATA mutation) .  We're a reference lab so many of our hospitals have different policies.  Some just give hemoglobin S negative, a few give C-E-K-HgbS- unless the Rh system is different and a few follow the same policy we have.  The information we've looked at indicates that there is no uniform policy among institutions regarding transfusion of these patients but it is nice to hear what others are doing.

As the antibody appears not to react with enzyme-treated red cells, I am just wondering if you have an auto-anti-Pr, rather than an auto-anti-I, the reactions of which should be enhanced by the use of enzyme treated red cells.