Gel vs. Solid phase

[cthherbal ☆]

We currently have a Provue and are considering switching to the Echo. I am looking to hear your thoughts if

anyone has already made the switch. Any additional comments on why you would or wouldn't switch.

Our main reason for considering a switch is reagent cost.

[Liz]

Hello cthherbal,

Other than the cost what else didn't you like about automated gel? We plan to get one and I am concerned.

Thanks,

[David Saikin]

When you look at the CAP survey reportings on methodology there was something like 1400 gel users and 89 solid phase users reporting . . . both technologies are good, esp when automated. I would be concerned with hidden costs in both systems AND service availability. I believe there is considerable wastage with solid phase plates.

[Liz]

That is good to know Dave. Thank you.

[AMcCord]

Wastage with plates for solid phase depends on what platform you are going to use. With manual testing and the Echo you use antibody screen strips that test 2 patient samples per strip. When I last looked at the Galileo (5 years ago), you could run 4 patient per test plate. That may have changed - I don't know. I also don't know what the Neo uses. Early on with the Echo, you had to use 2 test strips (which would run 4 patients) per run, sacrificing 3 antibody screens if you ran 1 patient. Now if you have a run that is for 1 or 2 patients, you use a balance strip so that large waste factor is gone. With 1 patient runs, you will still lose 1 antibody screen. If you never, ever run more than one patient at a time, you will lose 50% of your total antibody screens.

When cost per test is calculated, what you need to look at is how often you can 'batch' patient samples in runs of 2 (or 4 or whatever Neo uses) to determine waste. That percentage of waste is plugged into the reagent use formula and included in the cost per test figures. The Immucor sales people do that as part of your cost per test calculations (and very happily, too - naturally ;>). We calculated very conservatively and said we would have 40% waste and we still came out money ahead over gel for our contract with Immucor (3 years ago). Our actual useage pattern is better than 40% waste, as we are able to batch many of our runs with non-urgent tests like prenatal antibody screens, pre-surgical testing, next day transfusion patients and the like. So consider your work/patient order patterns when comparing automation methods. That should help make things clearer.

We have been satisfied with our Echo's performance and the technical support we get for it. I was concerned with how far away our service person is - about a 5 hour drive. BUT...we are in a rural area and that is not uncommon for service with any of the companies we do business with for hematology, chemistry, etc. The plus with the Echo is that it has been extremely reliable and we've only needed 1 service call in 3 1/2 years. All the other problems (and there have not been that many of them) were fixed by me with telephone assistance from technical support and a little box of parts that come with the instrument. **Disclaimer: I am definitely not a mechanically adept person, but I get alone with the Echo tinkering just fine.** It was designed for parts replacement by users, very simple replacement. Their capability to 'dial in' to the instrument, just like the technical folks do for the big chem analyzers allows for long distance diagnostics and adjustments to camera and centrifuge operation.

As of the first CAP automated survey of 2011, there were 407 Echos, 520 Provues, 130 Galileos, and 39 Tangos reporting. From the survey performance of each platform, I think you will see that they are all performing within acceptable limits. The switch from interpreting patient results in gel and interpreting patient results in solid phase is NOT difficult. None of my techs had a problem with that. (Note: we were manual gel users, not ProVue users.) We do have increased sensitivity, which is great for detecting alloantibodies in our patient population. We do see a few more warm autos that we did with gel, though that is a trade off I'm willing to make for the ability to catch a few more -Jk-a, Jk-b, Fy-a, Fy-b, and little c antibodies. We do not have an annoying number of non-specific reactions anymore (software upgrades, and a recent instrument adjustment, have helped that issue significantly).

Would I switch from the Echo to an automated gel system? If the ProVue has some new features that improve it's function over the function of the Echo and the money difference is significant...it's a possibility - gel worked fine for us when we were manual users. Am I satisfied with what I have right now with the Echo, functions and $$s...definitely Yes.

Edited September 2, 2011 by AMcCord

[Liz]

AMcCord, thank you for your time, that is valuable information and things that I certainly hadn't thought of. Great!

What is your manual method in case you need to do that? Gel or solid?

[AMcCord]

Glad I could provide useful information Liz.

We are using tube/PeG for backup and that is working well. That's what we did for our gel problem resolution, as well. We don't have to use it much, but it does help resolve some of our funky reactions and there are a few antibodies that like PeG better than solid phase - a few anti-Es (naturally occurring anti-E s perhaps??? since solid phase is looking at IgG antibodies) and 2 anti-K s in the last 3 years. An occasional antibody with a really low titer gets verified or worked up with PeG because we feel like we can get a closer look at the reactions.

I do have a manual solid phase station that I would like to set up (in my ABUNDANT spare time) for use as a backup in case the instrument goes down and to do selected cells for antibody ID. Since the instrument has been so dependable, that hasn't moved real high up my list of things I really really need to get done.

[cthherbal ☆]

Thanks everyone for your thoughts. It could just be my perception because I have used Galileos in the past, and I don't

remember having nearly as many HLAs as I see now detected in Provue/gel. Yes I have seen the CAP reports and I'm not so

much concerned with performance of one over the other.

[jlemmons]

I found this an interesting subject. A sister hospital to the one I used to work for did a study using the Echo, the Tango and the ProVue. There were pros and cons to each but overall the ProVue and the Tango actually showed the best sensitivity and specificity. However, recently there has been a carry over issue with the Tango and some people are questioning whether the Tango is really a good machine for their lab. While the ProVue has on occasion missed an antibody, they tend to be very weak and found only on homozygous cell lines. I've worked with the ProVue for about 6 years, at least, and have really liked it. Ortho is also upgrading software on the machines and showing customers how to decrease TAT with a change in the way the menu is set up. I've not really worked with the Echo but I have taught the theory of solid phase in MLT classes. I've also read at least one study that shows problems with the solid phase method. So I guess it comes down to what will work best for you and your lab. I have also heard that there will be some interesting things to see at AABB in the vendor section this year if you are going. Not my year to go though so I just get to hear about it. Good luck with your decision making.

[Mary**]

I hear that Ortho is going to release an updated Provue in 2012.

[John Hansen]

We run an Echo in our lab. We haven't had problems with it. I haven't had much experience with gel, but I work with techs that have, and they have no complaints with the Echo. The nonspecific reactions I have seen are rare. The only times we waste test strips are when we have very low volumes of patients. In addition, the turn around times seem much better than the Provue. From receipt to result, I routinely have my type and screens done within 35 minutes. If you do larger batches, that would increase to maybe 40-45 minutes.

My only complaint would be the way it processes blood types when you do a type and screen. It will start the antibody screen, then it will wait ten minutes or so before starting the blood type. I'm unaware of any issue other than software preventing quicker testing. Still, it has the blood type resulted about 8 minutes before the antibody screen. Our solution is if we want the blood type quickly, we do it by tube. No big deal.

I am also pleased with the many tests it can perform. It's saved us a ton of manual work we used to have to do.

[Auntie-D]

Is it still true that with solid phase you have no way of identifying mixed field populations. I've not used it since I was in training but it wasn't well thought of at the time as mixed fields didn't show up. There's a SHOT report where an ONeg patient was given APos in error and transferred to another hospital after having a massive transfusion reaction. The new blood bank typed him as APos and he was given further APos units and died.

Or has technology progressed since then

[John Hansen]

Is it still true that with solid phase you have no way of identifying mixed field populations.

It won't tell you there is mixed field. I think the best it would do is flag reactions that are weak, and it won't interpret reactions that don't make sense. It may also depend on facility protocol. We visually examine the pictures of the test wells before accepting results.

Also, I was wondering if you are referring to testing ABO/Rh in solid phase or in micro-wells? The Echo tests this with microwells and liquid reagent instead, so it is just like reading a mini-test tube.

[tbostock]

We just went live with the Tango and so far we love it. We are not seeing any "carryover", we tested that extensively during our PQ, and have seen no evidence of carryover. As far as strip waste, we maximize the strips by running 4 patients together whenever possible; we have enough volume on day and evening shift to be able to do this. A lot of our false positives on gel are not demonstrating on the Tango, so we are very happy.

[simret]

Gel is better in a way that you won't see a lot of "question mark reaction". Either it is weak pos (pos) or negative reaction. In Solid phase, we had problems grading the reactions. Having said that, you have to make your own judgement calling the strips pos/neg even though Immucor gives you a grading cut off. Basically, a lot of question mark reactions that we don't usually see in gel method. If you have any question let me know( inducing Neo). I have worked with Provue for while and I did not see as much problem as Echo Immucor Analyzer.

Simret

[simret]

Yes, as far as I know Ech/Neo does not recognize Mixed field. It will flag as inconclusive result and then you will have to go and see the reaction and also the patient's transfusion history , then you will make the call as mixed field. The reaction looks like 3/4 reaction and also free cells around the 3/4 reaction. That is mixed field.

Simret

[AMcCord]

One little tip for Echo users.......if you are getting unusual numbers of '?' results that look negative when you look at the screen shot of the test well, and you've had your Echo for awhile....ask service to clean the mirror in your camera and/or replace the camera. We started seeing an obnoxious number of reports with ? (false) results on antibody screens. When our service engineer came out to work on that problem, he discovered that the mirror inside the camera was extremely dusty - we have a very dusty lab for unknown reasons. He replaced the camera and the ? results went away. As dirty as the mirror was, he suspects that the dust was the problem with the well image. The negative results are now all crisp, clean and pretty with no guessing whether they are positive or negative. In the past month, we have had zero questionable results.

If I were asked today whether or not I would keep the Echo vs the manual gel we used to use, I would say yes.

[OxyApos]

I've had an Echo for almost 4 years. I have had 3 service calls and our guy is 6 hours away. I use the Manual Capture for the few times the instrument is having maint. The former gel users that come to work here, including myself, think the panels IG has are awesome and make workups so much easier. We run all antibody IDs and TYSC on the Echo. We have learned to batch in 2's on day shift when the volume is heavier and there's always a routine specimen "waiting on a buddy". Other shifts have almost all stats are run one at a time if necessary. This method has proven much cheaper in the long run than tube or gel. We were having less experienced techs sending specimens to ARC reference lab off hours because they didn't know how to interpret their reactions. The Echo has really empowered them and we now send maybe 1 warm auto a month off. ( We have too few to justify the reagent cost and workups ). We run about 60 panels a month on the Echo and appx 30%of those are passive anti D. Most antibodies only require 1 panel if you learn how to evaluate the 3 cell screen and run the appropriate specialty panel in the first place. The ? reactions are judgement calls Blood Bankers make just like "sticky" and +/=wk reactions in tube have been made for years. I see virtually no colds, I, or rouleaux with the Echo. It is NOT cost effective to retest donor units, run babies, weak D, or do crossmatches on the Echo for us. We do tube AHG crossmatches after getting antigen negative units.

[jalomahe]

When you look at the CAP survey reportings on methodology there was something like 1400 gel users and 89 solid phase users reporting . . . both technologies are good, esp when automated. I would be concerned with hidden costs in both systems AND service availability. I believe there is considerable wastage with solid phase plates.

Make sure you are looking at the correct CAP survey.

I'm thinking you are looking at the J survey which is not the one used for automated testing.

The most recent (2012) JAT (Transfusion Medicine Automated Testing) survey had the following number of participants.

Ortho ProVue = 524

Immucor Galileo = 106

Immucor Echo = 466

Immucor Neo = 21

Biotest Tango = 62

So in essence thats 524 Gel; and 593 Capture Solid Phase; and 62 Solid Phase.

Originally JAT only had participants report ABORh and Antibody Detection. In 2011 they upped it to include Antibody Identification. This year they also have included Compatibility Testing. If you can get your hands on copies of the Participant Summary, especially over the past couple of years, it can give you a bit of an overview of how the various analyzers are doing.

Wastage with solid phase automated analyzers can be an issue especially if you run low volumes however as stated by others it can be managed by using routines to pair up with STATs so you are leaving empty wells on your strips. But, don't forget to figure in all of the other consumables you won't be using with i.e. tubes, pipets, etc PLUS your valuable hands on tech time between the various methodologies whether manual or automated and whether that offsets the wastage issue.

[cthherbal ☆]

Thanks everyone. We are staying with the Provue for now...

[brobinson]

You have probably made a decision by now. If so, which one did you select? I am used to ProVue and have moved into a position at a different hospital with ECHOs. We have 2 at one site and 1 at another site and we constantly have problems. We have positive reactions on the ECHO in screening and antibody ID but if tested in PEG they are negative. Then the machines missed known antibodies that are positive in PEG. We are at a loss as to which method to trust. We are assigning mulitiple non-specific antibodiess due to reactions on the machines. Then the machine misses Anti-Es but picks up Anti-FYa. Very concerning.

[simret]

Good choice .