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Antibody I.D. Work-ups


klsmith

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Hi All,

I was just wondering, when you work-up antibody identifications, how do you do it? We just got a new supervisor at my hospital, and he has recently changed our SOP. It is very different from the way that we have always been working-up antibodies, so I am trying to find some kind of validation from Blood Bankers all over the world about this new process (if that makes sense).  Anyway, our "old" process was that we would set up the Ortho panel A and B initially, whenever we would get a positive antibody screen (kill two birds with one stone). If we were still unsure of what the antibody was, then we would set up a panel C and possibly a ficin panel (if we suspected something that the ficin panel could assist us with, which is normal). We also have the Immucor Panocell 16 that we can use, which we use as a last resort panel since it does have a nice extensive phenotype available for it's cells. With our new policy, we are only allowed to set up a panel A. If that panel is positive, and we think we know what it could maybe be, we are then required to set up only the negative cells for the antigen that we think we have the antibody against (again, I hope this makes sense) on panels B and C (as opposed to setting up the whole panel). We are also required to perform a DAT on every patient that has a positive screen as well (regardless of the autocontrol). Our new supervisor says that this is how reference laboratories perform antibody I.D.'s, and I am just wondering if anyone can vouch for this and tell me if it is correct. All the tech's in my Blood Bank are upset about this change, and I figured that this was the best platform in which to reach out and get feedback and information. Please advise if you can, any and every Blood Banker. All input is so super helpful and needed!

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Hi klsmith,

I am now retired from the Reference Laboratory, but there is NO WAY that we would just have used red cell samples that we knew were going to be negative (or expected to be negative); indeed, if we suspected a mixture of antibodies, we would set up a cell sample for each suspected specificity, but one which are negative for the other antigen(s).  For example, if we suspected a mixture of anti-D+C+E, we would set up a panel that included an example of an Ro, an r'r and an r", as well as a selection of rr cells, expressing all of the other clinically significant antigens.  In the UK, we believe that any specificity should be "proved" with two red cell samples expressing the antigen giving positive reactions, and that, wherever possible, a specificity should be "proved" to be missing with two red cell samples expressing the antigens giving negative reactions.

I attach the antibody algorithm I put together for NHSBT Reference Laboratories some years ago now.

Antibody algorithm..ppt

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In the US we have been doing what you say is going to be the new policy for many years, except we only would do a DAT if the autocontrol was positive.  I think that approach is pretty common.  Orthos' panel A is for the ijnitial assessment.  Most of the time, you will have a pretty good idea what you are dealing with with those results.  Then, going by the 3 x 3 rule, w use other panels for rule-outs / rule-ins.  Also, if there is no history, we antigen-type the patient for those antibodies that are being made.

Scott

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I like the way your new supervisor has you performing antibody ID and panels.   Why would you continue running full panels after the first if you can start narrowing down the specificity after the first panel and run selected cells?  For example, if you suspect the patient has anti e, why run any more e+ cells? 

 

Not sure I agree with the DAT if auto control is negative.  I think many transfusion services do not do this but I imagine that reference labs do.    There may be times when running a DAT is advised when autocontrol is negative but running DATs routinely when an auto control is negative will just take you down a path that will delay blood transfusion IMO

 

Edited by R1R2
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We start with one panel (or cells 1-10 of Immucor's Panel 20 if doing tube testing). If a specificity is apparent when crossouts are done/the pattern of reactivity is reviewed, then we use selected cells (negative for the antigen the antibody reacts with) to complete rule outs OR if a number of rule outs are needed, run another panel on the Echo. If the patient has a more complex history or the antibody screen looks more complicated, we might choose to run 2 panels on the Echo right away. I require 3 antigen positive cells which are reactive and 3 antigen negative cells which are non-reactive to 'prove' specificity. The patient is antigen typed for the specificity identified if not previously typed for that antigen and if not recently transfused. Other common clinically significant alloantibodies are ruled out with 2 cells. This works well with straight forward, single specificity samples with antibodies like anti-K, anti-E, anti-Fya, etc., which are the majority of what we see.  If the antibody screen on the Echo is positive in all three cells, which happens occasionally, we run a tube/PeG screen with an autocontrol plus one panel on the Echo with some questions in mind - is it an autoantibody? is it solid phase speficific? is it multiple antibodies? is it directed against a high incidence antigen? could there be a drug involved (anti-CD38, I'm looking at you!). If the auto is positive, we do a DAT.

If the specificity is not readily apparent, then we run another panel, or two, or three as needed, based on what the first panel looks like. Almost all of our IDs start on the Echo and those panels are pretty well designed for rule outs of the common offenders. It is not uncommon to use only one panel for some specificities. I encourage everyone to look at the big picture, then narrow their search based on what they see. In the long run that will save them time (and reagents). And I will admit that on a busy day, we may put 2 panels on the Echo and push GO to expedite things a bit. If we are doing tube testing, running extra panels we may not need up front, is probably going to use more time and effort.

Change is uncomfortable, especially for blood bankers, but give it shot. Think the steps through and work smart. You'll start to see problem solving in a way that you hadn't seen it before. Ask your work buddies for a second opinion if you're not comfortable. Review some cases with your supervisor to really get a good feel for what he/she is asking you to do. Once you've worked through the process it a few times, you'll feel better about it. And for those ugly case - the folks at the reference lab are your best friends!

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You didn't say how large your laboratory is and how Transfusion Services is staffed on the night shift.

When I was doing manual testing, it was consistent with your new supervisor's approach.  An autocontrol was only run with the first panel only.

With automated gel testing on ProVue, only full panels can be run.  Rule-outs are done by entering panel test results into the AntigenPlus antibody identification software.  A maximum of 3 panels would be run before sending specimen to reference lab.

This standardized protocol was used in a small hospital transfusion service (<1000 rbcs transfused annually) staffed with generalists.  This protocol was easily followed, even with only 1 generalist on staff at night for the entire laboratory.  

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Sometimes adaptations are made depending on limiting factors.  Maybe time is of the essence because the patient is bleeding or going into major surgery so more panels or methods are run at once to arrive at a conclusion more quickly.  Sometimes there is only limited amount of patient plasma so fewer tests are run at a time and further testing determined based on the results of early testing.  I always say that after the first panel with usual algorithm for rule-outs it ceases to be as much about the usual rules and starts to be more a matter of judgment and experience.  The "rules" help newer people and generalists stay on track.  If it gets complicated, they can call on more experienced people, including waking me up at 2 AM if need be.

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Firstly kudos for taking the initiative and getting outside opinions to the changes you are experiencing and are uncomfortable with. The above comments (from way more experienced blood bankers than I) indicate your new supervisor is not wrong but needs to clarify the new process in context for you all. I suggest following AMcCord's advice and pulling some past work-ups (or invent them). Include patients with a new and previous single antibody, also patients with new and previous multiple antibodies. Then get the supervisor to walk through how he would resolve them and explain how each work-up would change with a negative and positive DAT.

Running a DAT with each work-up is fine as long as it is clearly laid out what you are to do with the results and why. Once you have "proved" an antibody according to policy, running only negative cells for that antigen is normal practice because it is efficient (especially for the anti-e mentioned above). This is however assuming you have manual gel, as Dansket said only full panels can be run if automated. Hope this helps.

 

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  • 3 weeks later...

We do as your new supervisor states but without the DAT (unless the autocontrol is positive). An even when a patient has a history of let us say, little-c, we only run the cells that are little-c negative. By this time you should have done a screen and determined that little-c was still present. Anyway, this will allow you to waste time on cells that will ultimately be positive and not useful to rule out the other clinically significant antibodies. There is no need to re-identify little-c again anyway, since you have a history and are required to give little-c negative red cells. 

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  • 2 weeks later...

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