Troubles with Anti- D Reagent on ECHO???

[Linda0623]

Hi all,

I have a new problem where now that my validation is done for the ECHO, we are starting to see discrepancies between historical Rh types (Rh+) testing as Rh(-) on the ECHO..... We have had 2 of these cases recently, where if the current samples were retested in tube, they tested rh(+), thus consistent with their respective histories. What complicates this issue is that many of my patients are also autologous donors, therefore, we test Weak D on them (the donor tube) as well. On the ECHO, one tested Weak D positive, the other did not. So....for now I have my techs retesting on the bench in tube, and performing weak D testing on the ECHO, if there is a discrepancy with the history, to try to get a handle on where the discrepancy is, and how often does it really occur....

Any thoughts on the cause or how I should further handle this????

[krichards]

We have this happen occaisionally. I'm pretty sure I remember others posting similar remarks in this forum, as well. There doesn't appear to be much you can do about it. For me, this is just one of the Echo's quirks. (Every methodology has something!)

I gave the idea of repeating all Rh testing in tubes some thought (not much). It's just not worth it in my opinion. For the patient with no history, we would consider the patient Rh negative, and never know one way or the other. If the patient has a history of Rh pos, then we will retype in the tube. We have seen <10 of these since our go-live in May. Of these, probably 1/2 typed as <2+ in the tube. If you were not already aware, the Echo only reactions 2+ or greater positive.

[Linda0623]

Thanks K.....as they say, there is NO perfect blood bank method, and in our specialuzed scope of practice (predominently orthopedic), we miss most problematic Rh issues, such as those involving OB.....but, the techs were confused by this, and so it's great to be able to attribute this to assay limitations......

[clmergen]

We just had our first case like this on the Echo. Chapter 12 of the Operator's manual has the limitations of the method. And it covers that the Echo will not be able to detect reactions that in the tube would be 1+ or less. In our case, the tube test was 1+.

[Phylle]

We had 2 similar cases like this while we weretesting the ECHO. I'm not thrilled. We're just going to check any discrepancies with tube. We only do weak D on babies. I comfort myself that it's better to give Rh neg blood than vice versa.

[clmergen]

That's exactly what we are doing. Discrepancies are tube typed and those results entered. And the discrepancies aren't just with the D reactions. Those weak reverse typings will cause an NTD result. I had one of those yesterday.

Having the instrument do almost all of our work is well worth the few discreprancies that we have to tube type. We are having some of our busiest days this year but I am not hearing the staff complaining about the workload.

As one person put it after hearing the sound of the Echo shake the strips - "that is the sound of something else doing my work"

[Mary**]

Scary........

[RR1]

If anyone runs their ECHO 24hrs/ day- even for small number of samples- please could you tell me how often you change your ABO grouping reagents, if you leave them onboard the analyser all the time?

Thanks

Rashmi

[AMcCord]

Some of the discrepancies you are seeing with D typing may be the result of using different blends of anti-D monoconals, not because you are getting an error in testing. The clones in anti-D Series 4 and Series 5 may not be the same as the clones in your tube testing reagent. Rh typing for donors vs transfusion is kind of comparing apples to oranges really.

The 16th ed of the Technical Manual has done a pretty good job discussing this issue in Chapter 13. In particular, you might want to refer to pgs 396-399, Testing for D (Reagents, Donors, Patients, D Typing Discrepancies, and Clinical Considerations).

[JoyDenver]

We have just implemented our Echo last week. What I have observed with D teating on the Echo is the Series 4 will be negative and the Series 5 positive. I wonder if this is an indication of Partial D. We use Series 4 in our tube testing through weak D to confirm, but interpret on an individual basis (calling the Patient D neg and the Donor D pos). The Echo REALLY likes to find RhIg. Even if we repeat a screen or panel with PEG, the tube method is neg; we report the ab screen as neg in these cases. It's hard to convice our bench techs to love the Echo with these quirks just yet

(they, like most other Blood Bankers expect perfection) but, it won't take long for them to realize that the sensitivity is better than our manual method, and the bigger point, our manual teating will be reduced significantly reducing stress in our busy blood bank.

[Vaatha]

Our trainer and installer with Immucor was very clear about not having all reagents on the Echo more than 12 hours at a time. If they are on for >12 hours, then the reagents expire in 72 hours-except for the Indicator cells, which have to be changed every 24 hours anyways. We are still validating, but due to her recommendation, have come up with the plan to have 2 separate sets of reagents (all the same lots, of course) that we change out at 9am and 9pm. That way we wouldn't have degradation of the reagents to worry about, or having to discard a bunch of reagents because they were left out too long and thus shortened their expirations.

[clmergen]

We have a set of reagents for each shift. They only stay on the instrument for 8 hours per day. The 2 exceptions to this are the indicator cells that expire in 24 hours anyways and LISS because we use it up in less than 24 hours. This has worked very well for us.

[bpkelly]

We purchased extra reagent racks and set up a set for each shift.

[kharbert]

Discrepancies between tube and Galileo D typing results were discussed in a previous thread. Series 4 and 5 and the Immucor tube Anti-D defiinitely use different clones. What if these discrepancies are due to different epitopes expressed on partial D cells that are being picked up by some clones but not others? Seems that we would want to call partial D cells Rh negative. Immunohematology published a comparison of commercial anti-Ds and found that they had very different reactions with different partial Ds. The references were cited in the Galileo thread.

[RR1]

If ABO and Rh D typing reagents are kept on board for 12hrs at a time- do these reagents not start deteriorating after a certain amount of time, placing them back into the fridge does not necessarily set the 'clock' back to zero.- there must be an accumulated total.

If you keep moving your reagents between 4'C and room temperature- it is likely you will 'stress' them to an extent over time. Validation would need to be performed by looking at titres and possibly even looking at microbial contamination as well, over the maximum time used.(this could be a month or more-depending on your workload !)

Is it acceptable to carry on using these reagents for up to a month or more with the accumulated time kept at room temperature?

The whole concept of manufacturers setting time limits by which reagents should not be used is based on validation by them, if we go against their stated recommendations/ product inserts- then we ourselves are taking the responsibility (product liability) - when incorrect results are produced.

Rashmi

Edited March 5, 2009 by RR1

[John C. Staley]

For years (1999 to present) on the ABS2000 and then on the Echo we rotated the regents between the instrument and the refrigerator every 24 hours. We did this by having 2 racks and changed them out everyday when we did daily PM and daily QC. In all that time we saw no indication of problems resulting from this practice.

[Tony Lyn]

Hi all,

I have a new problem where now that my validation is done for the ECHO, we are starting to see discrepancies between historical Rh types (Rh+) testing as Rh(-) on the ECHO..... We have had 2 of these cases recently, where if the current samples were retested in tube, they tested rh(+), thus consistent with their respective histories. What complicates this issue is that many of my patients are also autologous donors, therefore, we test Weak D on them (the donor tube) as well. On the ECHO, one tested Weak D positive, the other did not. So....for now I have my techs retesting on the bench in tube, and performing weak D testing on the ECHO, if there is a discrepancy with the history, to try to get a handle on where the discrepancy is, and how often does it really occur....

Any thoughts on the cause or how I should further handle this????

Hmmmm.....Just wondering out loud. Would this character flaw apply to big brother Galileo as well as the technology is the same?

[Linda0623]

I don't know for sure, but my sister hospital has the Galileo....I can ask their experience.......

[silverblood]

So the debate rages on about the Echo anti-D's. Even though I have had it explained to me a couple of times by the Immucor reps. I guess I still do not understand the necessity of doing two different tests for Rh. Why isn't one good enough? Is ther some sort of problem with Immucor's anti-D reagents that they need a 'back-up' D? I understand that the reagents are two different clones of D-but I still don't understand why you need the two tests for the D. Is it that a monoclonal blend reagent for D does not work on the Echo? Is doing the two Ds on the Echo more accurate than doing one test for D in tube or with gel cards? Or does it just add confusion? Well-I am confused.............can someone help me out. Our lab is in the process of evaluatiing instrumentation for our lab................

[PJK3B]

If anyone runs their ECHO 24hrs/ day- even for small number of samples- please could you tell me how often you change your ABO grouping reagents, if you leave them onboard the analyser all the time?

Thanks

Rashmi

We run the Echo 24/7 and we have two racks for two of our three Echos and we switch the racks out at least every 8 hours.

pam

[RR1]

So the debate rages on about the Echo anti-D's. Even though I have had it explained to me a couple of times by the Immucor reps. I guess I still do not understand the necessity of doing two different tests for Rh. Why isn't one good enough? Is ther some sort of problem with Immucor's anti-D reagents that they need a 'back-up' D? I understand that the reagents are two different clones of D-but I still don't understand why you need the two tests for the D. Is it that a monoclonal blend reagent for D does not work on the Echo? Is doing the two Ds on the Echo more accurate than doing one test for D in tube or with gel cards? Or does it just add confusion? Well-I am confused.............can someone help me out. Our lab is in the process of evaluatiing instrumentation for our lab................

Do you mean the use of 2 x D reagents or the fact that there is a weak-D test function?

I have to admit I feel happier with 2 x D reagents just in case one was contaminated by splash over in reagent dispensing. The grouping on Galileo and ECHO is liquid phase in microplates where there is more potential for cross-contamination to happen.

We don't routinely weak-D test our negative reactions in the UK

[LaraT23]

I was just at a really great half day technical conference where Marilyn Moulds ( hi Marilyn if you are out there) gave a great lecture on this very thing! Her example was Ortho, in that the gel cards on the provue do use a different clone mix than the bench reagents. She found discrepant D typings when subsequent patients were run on the provue after being typed on bench reagents. Her recommendation was to send these off for molecular testing if it continues. I have the power point slides if anyone is interested. Just email me: lthedford@petersonrmc.com