Gel use by reference labs

[jerriemc]

This is a question I have asked several Ortho gel reps/trainers etc and they never can answer. If gel is so superior to the tube method why doesn't the Red Cross reference lab use the gel system?

[Rh-fan]

Fist of all, every firm will say that there methode is superior to any other methode. It is up to us if we believe these uprated 'car-sellers'.

Second, it all depents on where you work and what you do. I am at a reference lab and we use tube-PEG as our standard tech, and it is more sensitive then any other tech. (there wil allways be samples that are only reactive (with a relevant antibody in it) in one technic and not in an other, but that goes 2-ways). This is a group of experianced MT's that are are only doing antibody investigation every day.

When you are woking in a hospital with a lot of different MT's that only do bloodbanking sometimes (and during weekend/late/night shifts) I would go for any kind of (automated) gel or column system. With less experiansed MT's gel (or column) is more sensitive than tube. And when in doubt you can always let the result be read by every MT in the lab, try that in tube (you have to do the hole test again to see exactly the same reaction).

My choise would be, ref lab --> tube, hospital --> gel.

Peter

[JohnConnolly]

The MTS gel system is being used at the ARC in my state (MA). The reason being that most of their hospital clients are utilizing this system and they need to be able to duplicate reactivity. As you may know, this isn't always possible from one method to another.

[Rh-fan]

You are correct John,we also have different gel technics to duplicate reactions of hte hospital if the tube test is neg, but almost always gel is the second technic, not the first.

[Malcolm Needs ☆]

I also agree John.

[galvania]

The important thing is to choose a method and equipment that suits your needs. If we are going to compare to cars (as Rh fan wants to compare the companies to 'car-sellers') it would not be any more appropriate to drive a tractor on the motorway at 30kmh to bring your kids to school than it would to use a Fiat500 to try and pull a caravan. The gel technique is an excellent technique for routine use. It is easy to use, easy to interpret and easy to document. It is not, however, always the most appropriate technique when you are using 'home-grown' frozen down cells, or specialised techniques, or when there might be interference with cell buffers. Typically, the reference centres end up with the hard-to-identify samples, where it is possible that a number of different techniques might be needed to solve the problem. There will always be antibodies that come up with 1 technique and not another - and that can work anyway across the range of techniques available

[Malcolm Needs ☆]

Agree 150% Anna (if you excuse my maths)!!!!!!!!!

[jerriemc]

We are currently using the gel method, but we have had several occasions where we have gotten reactions on our screening cells and panels that we cannot definitively id the antibody. We send the specimen to ARC ref lab and they get all negative using the tube method. I understand that the gel picks up alot of nonclinically significant reactions. The problem is the pathologists and most techs do not feel comfortable giving blood to a patient that we get such strong gel reactions on and then ARC tells us everything is negative. On occasions such as this I am often asked by techs why doesn't ARC ref lab use the gel system? Thanks to everyone for their input.

[Malcolm Needs ☆]

The problem is the pathologists and most techs do not feel comfortable giving blood to a patient that we get such strong gel reactions on and then ARC tells us everything is negative. On occasions such as this I am often asked by techs why doesn't ARC ref lab use the gel system?

The thing is that the Reference Laboratory is trying to detect clinically significant antibodies (as you say, gel does detect an awful lot of clinically insignificant antibodies) to ensure that any blood transfused is as safe as any blood that is transfused. To do this, they do not want to detect "gel only" antibodies, and neither do they want to delay the transfusion for unnecessary reasons, such as clinically insignificant antibodies.

In my own Reference Laboratory, our first line of attack is Bio-Rad (used to be DiaMed) gel technology, but if we get non-specific reactions, or an anti-M, anti-P1, etc, we will repeat the tests in tubes, and, if there are similar results in tube, we will take things further until we get to the bottom of it (or run out of ideas), but, if we get clear negative results by tube technique, we will report both results, but give advice as to what blood to give, and how to cross-match it.

So far, after well over a decade of using gel techniques (nationally in England) no patient has undergone a transfusion reaction as a result (except, of course, things like hyperhaemolysis, which cannot be predicted serologically anyway).

Now, in the UK of course, the hospitals pay, within reason, the same amount for however many different techniques we employ (for example, if we receive a sample that is DAT positive, we could solve it quite quickly using gel techniques and the tube techniques, or it could involve us performing alloadsorptions, followed by tube IAT using monospecific anti-IgG reagents, possibly thermal amplitude tests......all sorts of things), but they get billed the same amount. IN the US, I think this is different, is it not? If the Reference Laboratory performed gel techniques as well as tube techniques, etc would you not have to pay more (I don't know; I'm only asking)?

[JoJo Smith]

This is a question I have asked several Ortho gel reps/trainers etc and they never can answer. If gel is so superior to the tube method why doesn't the Red Cross reference lab use the gel system?

Our ARC IRL implemented Gel testing years ago when our hospitals did, so we could see what they were seeing. It was a big learning curve. We found that warm autoantibodies and antibodies towards antigens in the CH/RG, Knops, and COST systems do not react the same in Gel as they do by tube. In Gel, both types of antibodies can be 2+ with a few cells and negative with others. This is neither textbook reactivity nor reactivity experienced staff have seen in tube for these specificities. When we first implemented Gel, hours were spent trying to identify the antibodies. Once this type of serology was observed in many patients and was proved either a warm autoantibody or an antibody in the CH/RG, Knops, or COST system, we stopped using Gel when the patient's DAT was positive. Our primary method is a Peg-IgG panel for any submitted sample, and if it is negative, we set up a Gel panel to see what the hospital saw. If alloantibodies are ruled out and the antibody has 'no apparent specificity', we do not try to categorize which specificity (CH/RG, Knops, COST) the patient has, which provides an answer quickly to the hospital. Both Peg-IgG tube and Gel are fine tests for routine antibody detection and identification until the patient has a warm autoantibody or antibodies to antigens in the CH/RG, Knops, and COST systems (often the reason samples are sent to an IRL), then in our experience, a Peg-IgG method is better.

[Malcolm Needs ☆]

Yep. Agree entirely JoJo Smith.

[snance]

While a useful method for antibody detection, it is controversial whether the Gel method is superior to tube methods in the investigation and identification of red cell antibodies. The American Red Cross has 40 IRL locations across the USA. With that number of IRLs, there are thousands of hospital and other blood center customers with different methodologies that refer samples to the ARC. The IRLs choose methods that are best suited to the majority of their local customers and methods that are able to detect clinically relevant antibodies as required by AABB Standards. Facilities with Gel as their primary method usually purchase the Gel screening cells along with the Gel panels premade by Ortho. This means that when the sample is referred to the ARC IRL, the commercially available panels have usually been tested and those panel results are submitted to the IRL. Retesting those exact panels is a waste of resources and the customers would have higher bills and a longer turnaround time for final results. To continue the testing in Gel, the IRL must prepare red cells from other manufacturers to use in Gel method. This is off package insert for those other manufacturers’ red cells. It still could be done, but there is an extra expense in time resources to prepare those cells. Some IRLs do prepare the cells and test by Gel, others use a method with similar sensitivity such as PEG, to investigate the reactivity as this is faster and gets the answer to the facility sooner. Other techniques such as adsorptions, enzyme treatment, neutralizations are often needed and the Gel manufacturers have not validated those sample sources for Gel testing. In house validations of the Gel techniques with those sample sources have not been uniformly successful. In conclusion, the ARC IRLs have many methodologies in their arsenal which are often needed, some IRLs have as many as 200 SOPs, and the ARC IRL Technologists are highly trained to utilize the best methods to obtain the answer. A useful reference is:

Determination of optimal method for antibody identification in a reference laboratory Immunohematology 2011; 27:146-150.

[Malcolm Needs ☆]

Agree entirely snance.

[Karen R]

I've worked in a Reference Lab for 25 years and can tell you that no one method is always perfect every single time. Sensitivity differences among the methods is just one aspect of why a lab may choose one technique over another, but tube testing is the “gold standard” and we are familiar with various potentiators that can affect tube tests. Automation in Blood Banking is primarily driven by the need for productivity, stable and objective endpoints, and flexibility for laboratories whose staff are inexperienced or intimidated by testing using tube methods. Shaking of tubes and grading of results are both technique-dependent and subjective. The automated and semi-automated methods flooding the market are a response to the changing laboratory environment of doing more with fewer staff, not because tube methods are bad or insensitive. There are fewer Blood Bank specialists to be found, so labs need a way to accommodate for that. Automated methods are the best way.

[tbostock]

We use 4 methods here: Tango (solid phase), gel, PeG, and MLB2 enhancement. So we use them all before sending to our reference lab. An example: we saw a high incidence antibody on both gel and solid phase, and sent it out, basically for rule outs. Their result was "negative results in tube testing". An expensive price for a method I had already done here. You can't just call it gel interference, if you are getting corresponding reactions in solid phase. Malcolm...comments?

[Malcolm Needs ☆]

Well the thing is Terri, that Karen R is absolutely correct in saying that tube testing is still the "gold standard" and will detect almost all clinically significant antibodies, but she is also absolutely correct in saying that the operator HAS to be experienced in the technique to perform it well. It does depend on the temperature at which the reactants are introduced to each other (e.g. have they been allowed to come to 37oC before they are mixed), how well the tests are washed, how much "bashing about" is used to dislodge the red cells from the bottom of the tube after the addition of the AHG and the final spin, and on the subjective reading of the results by a human.

Karen R, and others, are also correct in saying that no one technique will detect all antibodies. The gel and solid phase technology is very, very sensitive and will, on occasions, detect antibodies that are not clinically significant (actually, of course, the same can be said for tube techniques, e.g. anti-Ch, anti-Rg, anti-Kna, anti-McCa, etc), but here I mean antibodies that are incredibly weak, even if they have a specificity outside those mentioned above.

My question would be, of those that you have sent to ARC, where you have detected an antibody, but ARC have not, have any of them resulted in a haemolytic transfusion reaction when you have provided blood to the patient involved? I obviously do not know, but I am prepared to guess that the answer is no.

[tbostock]

Malcolm, we don't use ARC for our reference lab, we use our blood supplier. But when we have when we think we have a clinically significant antibody, confirmed by another method, we try to at least give antigen matched blood (as much as we can do here). So we have not had a hemolytic reaction, but we also don't just give any unit if we still think there is something there.

And I totally agree with you about tube testing, techs tend to "shake a little harder" if they see something they don't like.

We also sometimes don't have time or enough sample to send out to the reference lab because the physicians get very impatient and are totally OK with signing for incompatible blood. {{{{heavy sigh}}}}

Thanks for the very informative discussions above.

[Mabel Adams]

And yet, I have seen anti-Jka antibodies that are detectable in gel and not tube and I am glad I can find them because you can't necessarily say they are so weak as to be clinically insignificant with the Kidd system's tendency to anamnestic antibodies.

[Mabel Adams]

I think there is also an emotional level to this. When the reference lab tells us they don't detect anything, we feel like they think we are incompetent. We also feel like we have wasted money sending it out. I used to have reference lab techs that would sort of groan at us and wonder why we did gel testing at ll when their tube testing was so superior. All the things said above are true but a good customer service attitude and a good relationship with the reference lab go far.

[Malcolm Needs ☆]

And yet, I have seen anti-Jka antibodies that are detectable in gel and not tube and I am glad I can find them because you can't necessarily say they are so weak as to be clinically insignificant with the Kidd system's tendency to anamnestic antibodies.

True, but I say again, have any of them resulted in haemolytic transfusion reactions? Over in the UK, we had exactly the opposite, where anti-Jka was being detected in tube, but not in gel (Imelda Bromilow of, then, DiaMed did a lot of work on it), and yet, none of them caused transfusion reactions.

ANd the other thing to remember is that, these gel only anti-Jka's MUST have been around before gel was invented, when we only had tube techniques, and yet we didn't have haemolytic transfusion reactions happening due to anti-Jka all over the place.

I'm NOT saying that tube technique is the be all and end all, but it is still the "gold standard".

Edited July 27, 2012 by Malcolm Needs

[Malcolm Needs ☆]

I think there is also an emotional level to this. When the reference lab tells us they don't detect anything, we feel like they think we are incompetent. We also feel like we have wasted money sending it out. I used to have reference lab techs that would sort of groan at us and wonder why we did gel testing at ll when their tube testing was so superior. All the things said above are true but a good customer service attitude and a good relationship with the reference lab go far.

God help any of my staff that make the hospital staff feel inadequate or incompetent! They will learn within pecoseconds what I think of that, and they will be reminded that the hospital staff do exactly the same exams as do we.

[Steven Jeff]

I know from experience that Malcolm and his team are very supportive of Hospital based transfusion staff. Hospital based staff are always on the front line and often have to cope with haematology as well as blood transfusion issues and prioritising what is important at the time is the challenge.

Steve

[jerriemc]

Thanks to everyone for your replies. I must say we are very fortunate that our reference lab does not talk down to us or make us feel inferior, they try their very best to help us and even send reference materials. I ( and all my patients) are also very fortunate in that all my blood bank techs are very conscientous and worry about patient welfare. We all have a hard time issuing blood to patients when we have seen strong reactions in gel with our own eyes. Another reason we get so concerned may be that we are a relatively small hospital(100 bed) and we do alot of our phlebotomy and we get to know our patients well.

[StevenB]

Mabel's comment "we feel like they think we are incompetent" seems to have hit a nerve based on the responses. While her staff may "feel" that way, that perception could not be further from the truth. Mabel's staff is held in high regard, alway has been, always will be. Every effort is made to duplicate reactivity seen in hospitals throughout the region and Gel techniques are routinely used in that effort. Customer service is a top priority; again...always has been, always will be. Anything less is not acceptable.

[Mabel Adams]

I should make clear that my feelings were from some individuals (not the boss) at a previous reference lab, not my current one.