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QC on Panels


Kathyang
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We run a pos and neg with dilute anti-K when received and each day of use. Doesn't take much effort and it has passed several very picky inspectors.

 

 

Have you considered using a Fya control? It's more likely to pick up the cells going off than a K due to the Fya antigens disappearing off the red cells first.

Edited by Auntie-D
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Have you considered using a Fya control? It's more likely to pick up the cells going off than a K due to the Fya antigens disappearing off the red cells first.

OK, so you've proven that your panel can detect one antibody? What about all of the others? The purpose of the panel is identification, not detection. So...if you are truly QCing a panel you want to make sure it identifies all of your clinically significant antibodies at least. I totally agree with Bev Marotto...smoke and mirrors is not a game I like either.

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OK, so you've proven that your panel can detect one antibody? What about all of the others? The purpose of the panel is identification, not detection. So...if you are truly QCing a panel you want to make sure it identifies all of your clinically significant antibodies at least. I totally agree with Bev Marotto...smoke and mirrors is not a game I like either.

 

It's not about smoke and mirrors - it's about making sure that the weakest cells, that are likely to lose antigens first are still working. It is to determine if your cells are still viable for the most fragile antigens, it's not about reaction strength and the prozone effect. If a Fya control weakens with time it is an indicator that your cells are going off - all of them, not just the Fya.

Quality, not quanitiy...

 

As for quantification purposes - we do this every time we do a panel on a known antibody.

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Have you considered using a Fya control? It's more likely to pick up the cells going off than a K due to the Fya antigens disappearing off the red cells first.

 

When I first started doing QC on panels we were using LISS - since LISS and anti-K are not necessarily the best of friends, it seemed a reasonable choice at the time. I haven't changed that since we've switched to PeG (bigger fish to fry). It's one of those things that is hovering about mid-point on my to-do-list.

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:spotlight-right: We all agree that antigens deteriorate on red cells used for antibody detection and identification. What about compatibility testing performed on 42 day old donor cells? Subject to the same limitations? Have the Fya antigens have deteriorated enough so that the patient with anti-Fya will not have a reaction? :rolleyes::disbelief:  :shocked:

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Actually tricore, that may well be the case (sorry!).

 

The point being that the red cells used for screening and antibody identification are preserved in such a way as to maintain antigen integrity as much as possible (but certainly not oxygen carrying capacity) and are (usually) tested by something like flow cytometry to ensure that they are genuinely a "double dose" of, for example, the Fya antigen (as opposed to being, genetically FYA/FY).

 

On the other hand, the units that are being transfused, are in a preservative that will optimise oxygen carrying capacity, but not antigen preservation, and certainly you wouldn't know if the unit is genetically either FYA/FYA or FYA/FY, so you may well miss an anti-Fya in the cross-match - or, of course, any other antibody directed against an antigen that is rendered labile upon storage (and this depends upon, amongst other things, the anticoagulant into which the red cells were originally taken, believe it or not), and which has a possible null allele at the locus (which includes most genes that encode red cell antigens).

 

I repeat - SORRY!

 

:confused:  :confused:  :confused:  :confused:  :confused:

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Just a question - what does a Perpetual worksheet look like?   Would you be willing to post yours?  May just be semantics, but that one threw me.

It's just a worksheet that has columns for the 11 or 16 cells (depending on the panel) for rows and rows and rows ...

this way, it's easy to see the results from the previous panel(s) for comparison.  (ie. we are not recording the QC onto the antigrams supplied by the manufacturer).

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Well, the answer to that is, unfortuately, yes John.

 

There have been many instances recorded where, in particular, an anti-Jka has become labile, so that it is impossible to detect by normal serological means, but has caused a severe DHTR due to an anamnestic responce in vivo.  This is a function of the antibody, if you like.

 

Equally though, there have been many instances recorded where, in particular, an anti-Jka, that has later been demonstrated to show dosage in the pre-transfusion sample, i.e. during investigation of a DHTR, where Jk(a+b+) red cell units were apparently compatible in the cross-match, but which caused a severe DHTR.  This is a function of the antigen, if you like - with, possibly, a bit of an anamnestic responce going on as well, so possibly a function of both the antibody and the antigen, but there is, without doubt, a function of the antigen element there.

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  • 3 weeks later...

I use Ortho Panel A and Ortho Gel Screening cells. We run Ortho Confidence 1:9 daily on our screening cells. Thoughts on using the same dilution on the entire panel after receiving it to satisfy the product insert recommendation? "Periodically" to me is open to interpretation, just as the entire concept of running QC on panels is open to interpretation....

I figure if the control dilution is good enough for our screening cells used for detection, it is good enough for the identification.

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Isn't the very act of doing a panel also doing a kind of QC of the panel? Cells being positive or negative in a predictable pattern. When we get no reactivity or unknown reactivity on a panel we run a second panel to confirm the lack of a pattern or to find a pattern. With an allo we may confirm with an antigen typing. We are also confirming with xm of antigen negative units. The whole process of an antibody work up is check and double check.

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But...

Aren't we just saying that a system must be working OK because we like the results we get out of it?  If you are getting no reactivity or unknown reactivity on one or two or twenty panels, how do you know that the lack of a pattern is not due the panels being bad?

 

I think it is reasonable to say that the panels are OK as delivered due to the manufacturer's own quality program. (I just hope an inspector never asks for our proof of that!).  Having said that, the only "periodoc" QC that would seem to be needed is some sort of test before being used on patients (like that done with the screening cells - its a good point made above by Christy - if its good enough for those it should be good enouhg for panels).  This one-time QC on  panel would check that there was no deterioration in shipping.

 

Scott

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I bit the bullet and called CAP about QC on panels.

 

I asked what QC needs to be done to a new panel lot # when we first get it from the supplier with regards to COM.30450. Answer- You must follow the manufacturer's QC requirements. What does the manufacturer say needs to be done?  You must look at the shipping container. Was it shipped under proper shipping conditions? Yes or No. It needs to be visually inspected. Does it look normal? Is it hemolyzed? If it passes, it is OK to use without QC. If you use in-date panel cells as controls for antigen typing, it could be considered as QC to show that the cells work as expected. However special QC does not need to be done on new sets of panel cells. ( We use Immucor which says QC MAY periodically be performed. It doesn't say it has to be done.)

 

What about expired panel cells, what if any QC must be done? (TRM.31250) Answer- As long as you are performing the identification with in-date panel cells and only using the expired panel cells when the indate panel cells cannot provide what you need to rule-out or rule-in, the only thing that must be done is a visual examination. If it is not hemolyzed, it can be used without extra QC being done.

 

She said the key to both questions is antibody detection vs antibody identification. QC is done on the screening cells (detection) and does not need to be done on panels (identification).

 

And while I had her on the phone I also asked about IQCP on panels (just to make sure). IQCP does not need to be done on panels. Blood Bank will get off easy for the most part because IQCP mostly deals with kits with internal controls such as POCT and Rapid Strep kits where controls are not done each day.  I also asked about IQCP for tests such as Lui Freeze but she said IQCP was not needed. The reagents used for Lui would be QC'd the day of use, so IQCP is not needed.

 

I really wish the standards were a bit clearer on some of these things we stress over. I hope this helps answer some questions.

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Thanks very much for getting to CAP Debbie!  I still wonder what AABB/FDA/CLIA would have to say about all this (if you can even get them to comment in a useful manner).  Likewise JCAHO. 

 

And for those of us who use panels where the manufacturer's instructions read "should be tested periodically..." (Ortho - damne thee!), I think we are stuck at least doing some QC when the panel is first put into use.

 

Scott

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