Gel testing anyone?

[dotahill]

Hi all,

My lab is looking to getting gel, any suggestions or horror stories? Thanks

[Bill]

What is your goal by changing to gel? Gel is a good time saving method when testing multiple samples; however, it is much more sensitive than tubes methods and there will be times you will need to revert back to tube testing. Gel is not a cure-all for blood bank testing.

[LIMPER55]

walk away technology--idiot proof

not a cure-all for all blood bank problems and you will need to use tube testing for some things.

[adiescast]

The automated instruments are good technology and mostly walk away. Nothing is idiot proof. There are still decisions that must be made.

[LIMPER55]

The automated instruments are good technology and mostly walk away. Nothing is idiot proof. There are still decisions that must be made.

ok-corrected

[rravkin@aol.com]

Dotahill,

I agree with Bill except with respect to the time saving. Manual Gel testing really does not save alot of time as compared to the tube method. There is a 15min incubation followed by a 10min centrifugation, a very similar time frame for tube method. Gel has the advantage of less hands on work which would free up time for other work once the incubation is started. The columbs are easy to read however, as has been stated, the system is much more sensitive and therefore tube method is often used to resolve any questionable results. Manual Gel is the stepping stone to automation which offers greater consistancy in testing, and is walk-away capable, and any time saving over tube method would occur through greater volume testing. Good luck with you decissions and let us know how things go.

[jamato]

Just make sure you keep the Surgiscreen cells away from light. If you can, rotate the Surgiscreen cells between the shifts. They can easily get contaminated which can cause inconclusive results. At my hospital we keep them cover and on ice when they are at the bench. That has cut down on the number of false positves.

[Likewine99]

I have used gel since it first came on the market back in the early 1990's. I love it, would hate to go back to tubes as the primary testing method. The other posters are right, it's sensitive and is not the be-all. You will need an alternate methodology to back it up.

We've found that the gel anti-D reagent is more sensitive than the tube reagent. We've detected some Rh pos patients that were typed as Rh neg with traditional tube, they turn out to be weak D positive.

It works well if you have techs that are not dedicated to BB and does give you more walk away time. In the true stat situation you will still need tube testing. Reactions are stable, can be left for supervisor review.

[Abdulhameed Al-Attas]

You can ONLY expect to see AHG phase,NO RT and NO 37 Degree Centigrate reactions.

Edited March 30, 2011 by Abdulhameed Al-Attas

[jayinsat]

I say the benefits of switching to Gel as your primary methodology will outweigh any negatives that you will run into with Gel. As was previously mentioned, you will need to maintain a good tube backup method with either LISS or PEG for the "gel" antibodies.

[dgibaud]

One good thing is that everyone must do things the same way. No more "freelancing". You will still need tube methods for antigen typings. As others have said gel is an ultrasensitive system so you may need to do tube panels and/or xm's. It is certainly a more costly system when compared to tubes.

[Malcolm Needs ☆]

We think it is great.

We use it as the first line of attack, but, as others say, you must retain other techniques, such as tube, as it can be very sentitive (particularly with "cold" antibodies).

[hmust1]

I agree that you first need to evaluate the reasons you want to switch to 'gel.'

If it's to increase sensitivity over the tube method, then you might also consider the solid phase red cell adherence (SPRCA) method. If you want to improve productivity in your blood bank (while increasing sensitivity) then you should consider automating (with either Gel or SPRCA method).

[mminhas44]

we are also shifting to gel, ours is a new setup, not much workload and for the time being we have decided to only shift crossmatching on to gel, not the antibody screening and ID, and we DO expect false positives which we will cross check by tube method

[jlemmons]

We actually have three ProVues in our lab that use the gel technology. Most of the time, everything is negative and the type and screen are out the door. Occasionally, we will get something strange and will run a gel panel and end up using LISS and PEG and Ficin and everything else known to Blood Bankers to determine the antibodies. We also have been known to get what we call a "gel" antibody, where some patients just react with the gel and nothing else is positive. We back up to tube on these patients and AHG crossmatch units to be double sure there is nothing there.

[Steven Jeff]

we have decided to only shift crossmatching on to gel, not the antibody screening and ID

In all honesty mminhas44 I can't quite see the point of just crossmatching with gel. The biggest advantage of the gel technology is in antibody screening and identification. Whether used manually or on an automated platform it is the first line of testing for antibody screening for most laboratories.

Regards

Steve

:wave:

[tbostock]

Pros: less steps, no washing or check celling, reactions stay stable in the gel, more sensitive than tube testing.

Cons: sometimes too sensitive (warm autos go crazy in the gel), false positive problems with 0.8% screening cells, some techs stubborn reliance to tube testing (it was positive in the gel, so I did tube testing and it went away....grrrrrr)

[YorkshireExile]

One good thing is that everyone must do things the same way. No more "freelancing". You will still need tube methods for antigen typings. As others have said gel is an ultrasensitive system so you may need to do tube panels and/or xm's. It is certainly a more costly system when compared to tubes.

We do antigen typings with Diamed (now Biorad ) gel cards. We also do panels and XMs with gel cards. I only use tubes for the Immediate Spin XM. I haven`t used tubes for grouping, or pre-warm antibody screening or AHG crossmatch or antibody ID for a number of years now. I don`t really care about scruffy and weak reactions due to RT antibodies unless they are strong enough to affect my AHG crossmatch. Then I would simply send Malcolm my samples at the IBGRL for him to identify using all the wonderful tube methods. - Thanks Malcolm and team!

[Avid123]

"Gel-o-bodies" or "Anti-Orthos" are a problem as are colds and warms. BUT not every method will detect every antibody when it is present. Each method has it's own selectivity and sensitivity. We found this out when we were doing our side-by-side for gel and Solid phase (Tango). Gel is really good at detecting Rh antibodies. We have kept Gel and still use tube and PEG when necessary. Gel is nice, our techs took to it when we first got it. The Provue is a very primitive instrument-I refer to it as an automated workstation. Echo and Tango are better-true instruments.

[Malcolm Needs ☆]

Then I would simply send Malcolm my samples at the IBGRL for him to identify using all the wonderful tube methods. - Thanks Malcolm and team!

I really do wish that I could take the kudos, but, whilst I was trained at the IBGRL and worked there again for a short time as a locum, I don't work there now (although I do work in Red Cell Reference). The people who really deserve the kudos are people like Joyce Poole and Nicole Thornton, and their present team of very hard working experts.

[Eoin]

We have used gel for years and have encountered similar problems to all above. Despite that I am an advocate for their use. Far less messy - also very good (no - make that great) when you get called by junior scientist with a problem (particularly in middle of night) - because the cards are still available and able to be read by you. That doesn't mean you won't want to repeat testing for yourself - but a lot of basic groundwork will often not have to be repeated. For all that, we will never get away from tubes for some testing. We also use tubes for check grouping.

By the way, we got a non-conformance for describing our testing method as Gel in our Scope of Accreditation - it is actually column agglutination technique (CAT) - so our scope is now corrected, but we all still call it Gel.

Cheers

Eoin

[kharbert]

Two more observations about gel frommy experience in student lab: gel uses much lower volumes of patient sample, and the weight of biohazardous waste material is markedly reduced. I also agree with the precautions about using the screen cells. Also, early in gel marketing, anti-E's were missed if using manufacturer's 0.8% screen cells, but 0.8% screen cells created in the local laboratory by diluting 3-5% screen cells were able to detect the antibody. Presumably a problem with the preservative.

Another student lab observation: in tube testing, technique is so sensitive and important (don't resuspend cell button too vigorously/don't take inordinate amounts of time resuspending--don't make your cell suspension too weak/ don't make it too strong--etc). Gel testing frees you from some of these variabilities in technique so that you can focus on problem-solving and concept development. This observation probably also applies to training of laboratory staff. Technique in gel is still very important, just not as sensitive and subjective.

I'm a fan.

[Michaele]

It's also good for standardizing how reactions are graded. In tube, there can be a bit of variation between techs on how they grade reactions. In gel its a little easier for every tech to recognise 1+, 2+, ....

I agree with others that the pros outweigh the cons, and it is very good for antibody screen and id.

[Kathy]

One other thing I would like to mention is that the tube is more sensitive for the reverse ABO grouping. We do both tube and gel typing on all new patients and were noticing that sometimes the tube reverse would come up (appropriately) positive, but the gel was negative. I called Ortho tech support and was told that for low titer ABO antibodies, tube is more sensitive.

[Brenda K Hutson]

LOVE IT!! And I have pretty much used every method at this point.

I worked in 1 large Medical Center that used automated Immucor Instrumentation (ABS 2000 at that time). They were looking then at just moving on to the Galileo. I had used GEL previous to that and felt this Institution was one that would really benefit from GEL. Just one of the really nice things about GEL is that it takes away that subjectivity of grading reactions among staff (well, not entirely; but almost). That was a problem in that Institution. I was surprised how far off the grading of reactions was (when they performed Tube Testing; which they did for STATs and Antibody ID).

The Manager had already decided that they were going to get the Galileo (though she took several of us on trips to view both the Galileo and the ProVue). To make a long story short, they ended up getting the Provue. I actually transferred to another Hospital before that occurred but the Manager called me more than once to say how much everyone loved GEL and that she was glad I pushed for that.

Truthfully, I have never known of anyone who used GEL, that did not love it.

Brenda

Hi all,

My lab is looking to getting gel, any suggestions or horror stories? Thanks