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DAT PROCEDURE..


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  • 2 weeks later...

We are currently validating IgG DATs in gel and finding that many cord blood samples are at least a grade stronger in gel.  I am loathe to start doing adult DATs in gel because I suspect more pos autos on IDs will then show pos DATs in gel meaning we have to do more elutions because many of these patients are recently transfused. We have not had any patients suffer from our current process using tube DATs to follow up pos auto controls.  Did anyone else see a significant increase in pos DATs (especially non-cord blood) when they went from tube to gel?  If so, do you find it valuable or misleading?

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13 hours ago, MaryPDX said:

We've done adult IgG DATs in gel for the over a decade.  There was an increase in the number of positives (due to gel being more sensitive), but don't remember how significant it was.

 

I agree with you MaryPDX!!!

There was couple of times we got false negative DAT due to the technique we use. If you are using Gel DAT I would prefer to use analyser be cause transfused cell are at the bottom.  But if you are using manual technique probably you can use whole blood but that will clash with manufacturer instructions. 

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We've been running IgG DATs on our analyser (Provue--->Wadiana) for large part of that time. Although we have an Erytra, we haven't used it for DATs due to the lack of a positive whole blood control that the system would recognize as QC. 

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I get the impression that there is a significant difference between the sensitivity of the cameras on the Provue and the Vision with the Vision being more sensitive.  About 70% of our antibody screens get a "?" so we have to manually interpret the card.  This maybe be due partly to the problems Ortho has had recently with their IgG cards.  I'd be interested to know if anyone who has switched from a Provue to a Vision had information on this topic.

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On 1/16/2017 at 0:27 PM, MaryPDX said:

We've been running IgG DATs on our analyser (Provue--->Wadiana) for large part of that time. Although we have an Erytra, we haven't used it for DATs due to the lack of a positive whole blood control that the system would recognize as QC. 

You can create your own QC sample and use check cells or override the DAT QC altogether since you don't need to do it. the IgG cards and diluent are already QC'd.

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10 hours ago, MOBB said:

You can create your own QC sample and use check cells or override the DAT QC altogether since you don't need to do it. the IgG cards and diluent are already QC'd.

True, we do this for the Wadiana. It allows you to make changes as to the vials which run QC (i.e. Which vial you created as your positive DAT), but you can not make ANY changes to the QC vials that are run on the Erytra. The Erytra QC is hard coded. There is no access to the front end user, only Grifols technicians have access to that. Since Grifols does not make a positive DAT that the Erytra recognizes as QC, our facility has chosen not to use its DAT function. 

Once we get our second Erytra, we will lose our wadiana and then it's back to manually doing DATs (but at least it'll be in gel! ?)

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59 minutes ago, MaryPDX said:

True, we do this for the Wadiana. It allows you to make changes as to the vials which run QC (i.e. Which vial you created as your positive DAT), but you can not make ANY changes to the QC vials that are run on the Erytra. The Erytra QC is hard coded. There is no access to the front end user, only Grifols technicians have access to that. Since Grifols does not make a positive DAT that the Erytra recognizes as QC, our facility has chosen not to use its DAT function. 

Once we get our second Erytra, we will lose our wadiana and then it's back to manually doing DATs (but at least it'll be in gel! ?)

We test the DAT IgG on our Erytra and chose not to QC it since all the reagents and processes are already QC'd. There's really no need to QC the DAT itself.

What do you do for poly DAT?

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We aren't running poly DAT at this time. We're using the IgG gel cards and tube method for C3. (I have turned in my validation of using buffer cards with anti-C3, so hope to use that method soon. ?)

Once Grifols poly cards are available here, we will use them. 

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  • 1 year later...
On ‎1‎/‎21‎/‎2017 at 2:54 PM, MaryPDX said:

We aren't running poly DAT at this time. We're using the IgG gel cards and tube method for C3. (I have turned in my validation of using buffer cards with anti-C3, so hope to use that method soon. ?)

Once Grifols poly cards are available here, we will use them. 

Is there any chance you could share your validation? I'm looking to do something similar. Thanks!

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23 hours ago, MOBB said:

Is there any chance you could share your validation? I'm looking to do something similar. Thanks!

Did a total of 20 tests (combination of QC and patients).  Ran the C3 test manually (tube method, which was our standard SOP), and in the buffer gel cards.  Results of testing using both methods were recorded on paper for the Pathologist, Manager and our Technical Coordinator to view. They all had to sign off on the new method before the procedure was updated.

 

Procedure of buffer gel card method:

1. Bring your reagents, QC and patients to room temperature.

2. Make a 0.8% red cell suspension (of QC and patients.)

3. For QC, you will need a POS, NEG and a control well (pos control cells only in the control well).

4. For patients you will need 2 wells, one that you will add red cells and reagent to, other patient cells only. 

The reason for the red cell + buffer only wells is to ensure that no spontaneous agglutination is happening.

5. Add 50ul of red cells to wells

6. Add 25ul of anti-C3 reagent to reagent wells only (DO NOT add reagent to buffer only control wells)

7. Incubate 5 min. RT

8. Spin in appropriate gel centrifuge.

9. Record results.

Just an FYI, before you turn your findings in, make a copy of the paperwork, just in case someone loses it. (speaking from experience here).

Hope this helps.

Mary

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On ‎01‎/‎21‎/‎2017 at 3:54 PM, MaryPDX said:

We aren't running poly DAT at this time. We're using the IgG gel cards and tube method for C3. (I have turned in my validation of using buffer cards with anti-C3, so hope to use that method soon. ?)

Once Grifols poly cards are available here, we will use them. 

do you use Grifols for all your other gel testing?

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On 1/23/2018 at 1:46 PM, MaryPDX said:

Did a total of 20 tests (combination of QC and patients).  Ran the C3 test manually (tube method, which was our standard SOP), and in the buffer gel cards.  Results of testing using both methods were recorded on paper for the Pathologist, Manager and our Technical Coordinator to view. They all had to sign off on the new method before the procedure was updated.

 

Procedure of buffer gel card method:

1. Bring your reagents, QC and patients to room temperature.

2. Make a 0.8% red cell suspension (of QC and patients.)

3. For QC, you will need a POS, NEG and a control well (pos control cells only in the control well).

4. For patients you will need 2 wells, one that you will add red cells and reagent to, other patient cells only. 

The reason for the red cell + buffer only wells is to ensure that no spontaneous agglutination is happening.

5. Add 50ul of red cells to wells

6. Add 25ul of anti-C3 reagent to reagent wells only (DO NOT add reagent to buffer only control wells)

7. Incubate 5 min. RT

8. Spin in appropriate gel centrifuge.

9. Record results.

Just an FYI, before you turn your findings in, make a copy of the paperwork, just in case someone loses it. (speaking from experience here).

Hope this helps.

Mary

Did everything correlate well?

I keep asking my TAS about the poly card and it sounds like it might be a minute. She also said something about a poly/IgG/Complement/Control card being available first. Have you heard anything?

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On 1/10/2017 at 8:18 PM, Mabel Adams said:

We are currently validating IgG DATs in gel and finding that many cord blood samples are at least a grade stronger in gel.  I am loathe to start doing adult DATs in gel because I suspect more pos autos on IDs will then show pos DATs in gel meaning we have to do more elutions because many of these patients are recently transfused. We have not had any patients suffer from our current process using tube DATs to follow up pos auto controls.  Did anyone else see a significant increase in pos DATs (especially non-cord blood) when they went from tube to gel?  If so, do you find it valuable or misleading?

We do our DATs in gel and there is an increase in positive reactions compared to tube. At times it's valuable and at times it's misleading. It just depends on the case, but I appreciate being able to automate the test and standardized the reading of the results. 

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On 1/29/2018 at 10:33 AM, MaryPDX said:

Yes it correlated very well. 

As far as the Grifols DC card (DAT card), I've heard early 2018, but I haven't seen anything yet from FDA that it's licensed.

I've been hearing "just a couple more months" on the card and antisera for at least a year, maybe more. I am very happy with them overall, but I cannot wait for them to have their full line available.

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