Re-incubating a gel card??

[trnscs66]

Sorry if this thread doesn't go here.

Okay, this seems like a weird question, but my supervisor is pressing the issue: does it say anywhere (documentation) that you can incubate gel-card microtubes multiple times without removing the foil and have them be still good to use? I scoured the Instructions For Use and could not find anything with that kind of wording. It also doesn't state the contrary neither. I called Ortho tech-support and they stated something along the lines that "There have been no studies that have tested incubating multiple times before use."

Mind you, I've had rotations at other, larger labs that use the gel system. IMO, it seems obvious that you can incubate them a few times before use. Why else would they be designed as such?

Honestly, I don't think I'm going to find such documentation anywhere. This lab is going to be switching to the gel system for the first time and Joint Commission is right around the corner. Bottom line: I need a little help explaining to my sup that they're going to be okay and they're chasing red herrings. Tactfully of course! :D :D :D

Thanks!!

[NedB]

Well, you won't find that documentation, but here is some logic. The ProVue is the automated instrument for the gel system. When you prepare it for the day, you load a number of IgG cards onto the 37C rack. Guess what happens to the card or cards not used? They stay in place until you use them. That may be several cycles. At one time we acted conservatively and didn't load more than we could use, but as with many things, familiarity breeds not contempt, but relaxation. No harm has ever come to the cards. And think about it, the cards are sealed and the temperature does not rise above 37C, hardly a level to cause degradation.

[Malcolm Needs ☆]

I think that you have to look at the requirements for storage of the cards before use. Certainly, with the DiaMed cards we use in the UK, they have to be stored between 18 and 25 degrees C.

I wouldn't mind betting that the inspectors will regard pre-incubation of the cards at 37oC as being out of storage temperature range.

I know that any inspector in the UK (MHRA or CPA) would have a fit of the vapours if we regulalry did this kind of thing. We received a non-conformance for not having a minimum - maximum thermometer on top of each and every one of our boxes of DiaMed cards stored in our Laboratory.

:disbelief:disbelief:disbelief

Edited November 5, 2009 by Malcolm Needs

[Fluffy agglutinates]

This is a very interesting question! Can I ask if you are going to be using an automated system? If so you will find the answer out during validation! I would think the analysers will recognise a card which has been incubated but not used yet & reject it for you if it falls out of spec. It should also be set up to use cards in order of loading (avoiding the situation in the first place). DiaMed analysers allow a 37oC incubation maximum of 30 minutes per test, then it throws them away for you.

If you are using these cards manually then the storage temp should be adhered too i.e. like Malcolm said 18-25oC is your range. If you've used a part card then you've gone outside the recommendations (and yes we do this all the time!).

Thank you for bringing this up! I wonder that I've never considered it before now. I shall have to ask my local friendly reference lab...

[trnscs66]

Thank you everyone for responding!!

We're using a manual system. The Ortho cards do state that they should be stored at either room-temp or in a refrigerator.

I think I may get in touch with our reference laboratory myself. Would the validation process be that hard for the manual method? Maybe just incubate the card six to ten times and set it up with weak positive controls and compare the results to a non-incubated card?

Sounds like fun times ahead!

[Malcolm Needs ☆]

Thank you everyone for responding!!

Would the validation process be that hard for the manual method? Maybe just incubate the card six to ten times and set it up with weak positive controls and compare the results to a non-incubated card?

Sounds like fun times ahead!

No, it's not that difficult, just a bit time consumming.

Most of the NHSBT Laboratories are now automated, but my own is still totally manual, and we had no problems.

Enjoy the fun!!!!!!!!!!!!!!!!!

:D:D:D:D

[silverblood]

My hospital has been using the Ortho gel cards for quite some time now-we routinely re-incubate the gel cards-as long as the foil still covers the microtubes no harm will be done. Two patients' three cell screens will fit on one card so if you only have one screen to do if you did not save the card for an additional patient after the first one is done you would sure be wasting alot of gel cards!!! You can't always hope to batch patients just so you would use one whole gel card up.......................

[Mabel Adams]

It was certainly implied in our training by Ortho that the unused microtubes could be used during a later run.

[David Saikin]

I agree Mabel . . . we only defoil on set of microtubes (3 to be precise) if we have one pt to run. This seems to be standard at all places I have been to that use gel.

[Mabel Adams]

Wouldn't you think that all of us doing it this way would have sort of validated the heck out of it in all these years? Has anyone ever validated that sticking an applicator stick in a specimen doesn't absorb out antibodies? For that matter, did we ever validate glass tubes, or plastic pipets or... In fact, until recently no one had ever validated the usefulness of blood transfusion.

[RR1]

These manufacturers imply a lot of things but now-a-days I go with what our inspector said:

If it's not written down....it's a rumour.

[jlemmons]

As long as your total incubation time for testing multiples patients does not go past 45 minutes, I believe you are fine. My understanding is that that is the limit of how long the gel is valid at 37 degrees C.

[Malcolm Needs ☆]

These manufacturers imply a lot of things but now-a-days I go with what our inspector said:

If it's not written down....it's a rumour.

I agree.

The other bit to this is,

If it is written down, but is not signed and dated....it is graffiti.

:)

[adiescast]

OK, I don't use gel, so maybe I am speaking out of turn. It seems this would be easy to validate. Take a variety of positive and negative samples and use the cards as you normally do and check the results against the known. If I remember correctly, in manual testing the second set of microtubes will only be incubated twice, once with the first set of microtubes and once on its own (or have they added a third set of microtubes to the card since I looked at it?). This would give you your normal use or PQ. What is the likelihood of anything causing a card for manual gel to be incubated more than twice (or three times if there are three sets)?

The automated set incubation sounds like a whole different ball of wax, but as has already been pointed out that should have been covered in your instrument validation.

[keisterkid]

This reply is from an Ortho technical specialist:

I got an email with your concerns for testing the gel card with multiple incubation times. This question came up in my very early years (1995!) and the answer was yes there many studies done incubating actually hotter than 37C(up to 40C). One microtube was opened and incubated followed by the second one etc. until all 6 were used. The main reason heating does not cause a problem to the gel is the gel does not come in contact with heat…….only the upper reaction chamber. Important to keep the foil intact and not open and try to incubate using that well later. Drying could occur which would not be good. Also the package insert states that storage should be between 2 – 25C (not testing environment).

So the bottom line is ……..multiple incubation times does not affect the gel card. I hope this helps. Would be glad to talk to you or anyone else who is concerned about this.

[Steven Jeff]

Thankyou keisterkid. Your answer is so logical now I think about it. The design of the incubator is such that when you place the casettes in the incubator slots the glass bead portion hangs below the heat block. As you say only the reactants part of the casette touches the heat block. This is also the reason why it is important to ensure that the reactants remain at the top of the column for the incubation stage.

Steve:)

[jcdayaz]

This reply is from an Ortho technical specialist:

I got an email with your concerns for testing the gel card with multiple incubation times. This question came up in my very early years (1995!) and the answer was yes there many studies done incubating actually hotter than 37C(up to 40C). One microtube was opened and incubated followed by the second one etc. until all 6 were used. The main reason heating does not cause a problem to the gel is the gel does not come in contact with heat…….only the upper reaction chamber. Important to keep the foil intact and not open and try to incubate using that well later. Drying could occur which would not be good. Also the package insert states that storage should be between 2 – 25C (not testing environment).

So the bottom line is ……..multiple incubation times does not affect the gel card. I hope this helps. Would be glad to talk to you or anyone else who is concerned about this.

I have been trying to investigate the validity of doing "Prewarms" in gel. It was decided by the "powers that be" that we shouldn't do them in gel because the total time the gel card would be at 37degrees would be greater than 45 mins.

Is this a valid conclusion? We were told by our Ortho rep that a card could not incubate >45 mins. Is this correct?

[bb4me]

This is a very interesting question! Can I ask if you are going to be using an automated system? If so you will find the answer out during validation! I would think the analysers will recognise a card which has been incubated but not used yet & reject it for you if it falls out of spec. It should also be set up to use cards in order of loading (avoiding the situation in the first place). DiaMed analysers allow a 37oC incubation maximum of 30 minutes per test, then it throws them away for you. QUOTE]

We are using the Ortho ProVue. It does not reject an IgG gel card for having been previously incubated. It would reject that card if it saw other errors ("well incidences") such as bubbles or splashes. I am not certain if an unexpected volume level would flag the card for rejection before it is used, or if it would simply require a review after attempting to read the reaction.

[RR1]

For users of the Galileo (not ECHO), there is a risk that the Capture-R screening plate could be passed through the incubator for potentially up to 12 times if strips are not deselected and removed from the plate frame, with the liklihood of deteriorating the screening cells themselves.

This is far worse than re-incubating the gel cards.

[jcdayaz]

It was certainly implied in our training by Ortho that the unused microtubes could be used during a later run.

We do this practice also when we have manual testing that needs to be done. We will uncover only 3 of the 6 wells in an IgG card for one patient. Then we will save that card for use again for a different patient. But total incubation time of the card would be less than 45 minutes...ie..2-15 minute incubations.

I am still searching to find something written (and signed/dated, Malcolm:D) on prewarm testing in a gel card. I want to try to not have to wash tubes manually with prewarmed saline. Anybody doing this? Is it even a valid expectation on my part?

[Mary**]

We were not successful using the prewamed technique in a gel card. I think it is because of the 10 minute spin at room temp. Wish it did work.

[Malcolm Needs ☆]

I am still searching to find something written (and signed/dated, Malcolm:D) on prewarm testing in a gel card. I want to try to not have to wash tubes manually with prewarmed saline. Anybody doing this? Is it even a valid expectation on my part?

I know of Hospital Laboratories that do this jcdayaz, but it is not as effective as washing tubes manually with pre-warmed saline.

The reason I can say this with some certainty is because they will very often say that they have tried pre-warming the cards and got nowhere, before they send us the samples, but we find nothing by manual tube technique with warm-washing.

Sorry!

;)

[adiescast]

For users of the Galileo (not ECHO), there is a risk that the Capture-R screening plate could be passed through the incubator for potentially up to 12 times if strips are not deselected and removed from the plate frame, with the liklihood of deteriorating the screening cells themselves.

This is far worse than re-incubating the gel cards.

We do not put more strips on the plate than we need for the current run. Immucor has told us that we can put whole plates on, so they don't seem to see the multiple incubations as a problem. There is a time limit to how long a plate can stay on the instrument, but no information about how the strips are affected by multiple incubations.

[RR1]

We do not put more strips on the plate than we need for the current run. Immucor has told us that we can put whole plates on, so they don't seem to see the multiple incubations as a problem. There is a time limit to how long a plate can stay on the instrument, but no information about how the strips are affected by multiple incubations.

In the UK Immucor have issued a field safety notice about deterioration of plates if they repeatedly pass through the equipment. I will try and attach this to this thread on Saturday- when I get to work. If only they would standardise what they tell us all!!!

[Malcolm Needs ☆]

In the UK Immucor have issued a field safety notice about deterioration of plates if they repeatedly pass through the equipment. I will try and attach this to this thread on Saturday- when I get to work. If only they would standardise what they tell us all!!!

I thought your Lab was working well today!!!!!!!!!!!

:devilish::devilish::devilish: