Gel vs Tube methods in IRLs

[missyg]

I had a question about patient workups in the IRL. Do most IRLs use both gel and tube or one or the other? We were strictly a tube method IRL however most of our hospitals had gone to gel and we have now implemented gel as well. We have a lot of strange reactivity in gel that we cannot duplicate in tube. I know that there is not a 100% method of antibody detection but I was curious as to what other institutions are using. Thanks!!!!

[Malcolm Needs ☆]

Sorry for being an idiot, but what is an IRL?

If the "RL" bit stands for Reference Laboratory, I may be able to answer your question. If it doesn't, I may not be able so to do.

[missyg]

Immunohematology Reference Laboratory Sorry maybe I should have written it out.

[Malcolm Needs ☆]

Immunohematology Reference Laboratory Sorry maybe I should have written it out.

No, it's not you, it's just that we call it RCI (Red Cell Immunohaematology) over here.

We use DiaMed gel techniques as a first line of attack (IAT and enzyme IAT), but, if we have no joy with that, we will most certainly fall back on tube techniques, using either a polyspecific AHG or a monospecific anti-IgG reagent (or, on much rarer occasions, a monospecific anti-C3d reagent).

If we still have no joy, we will send the sample to another NHSBT-Centre, who use either Ortho BioVue or a solid phase microtitre plate technique.

Eventually, we will send samples to the International Blood Group Reference Laboratory.

We are extremely lucky in my Laboratory, as we usually have about 60 rare "liquid" red cell samples available for use, together with in excess of 690 frozen rare red cell samples and a vast range of frozen rare antisera, mostly from SCARF, so we are a bit unusual, to say the least.

[heathervaught]

Our Reference Lab has access to Gel if they need to correlate results to the customers' or if the situation warrants (I know there are scenarios where their SOPs require a Gel DAT). They do consider it on their continuum of enhancement media. However, from what I have observed, they usually rely on tube methods.

I think if you look around the site, there are quite a few discussions on extra reactivity in Gel. Anti-M seems to be one of the biggest problems (although it is clinically insignificant and cold-reactive, 50 to 80% are IgG or have an IgG component: Harmening Modern Blood Banking & Transfusion Practices, 5th ed., page 166)

[David Saikin]

I do reference work for a few facilities. I had to change methodologies (I chose gel) because my clients were getting reactions (1-2+ with gel) and I wasn't finding any reactivity with tubes (even peg+enzyme). Both systems, gel and capture, are prone to some weak reactivity that is both unresolved and seems to be of a spurious nature. It must be remembered that both of these systems are extremely sensitive. If my clients have the same lot of screening cells I am able to duplicate their weak + reactions. My lab has experienced very few of these in the 3 years we have used gel. I have found that most of these rxs are enzyme sensitive making me believe that I am seeing HTLA-like reactivity. Join the crowd!

[Eagle Eye]

Our IRL uses tube(they love tube) and do not use gel unless you specify or if they are not able to demonstrate any reactivity @ PEGAGT, @ Enzyme AGT with same specimen...THat is the reason we try not to send specimen which are too week...as they come bcak with non reactive. Our IRL wants to stick to tube eventhough they have lots of clients who uses gel. I do not know why?? I know one reason tehy gave me was they can not DTT treat or CHloroquin treat teh cells...they can validate??? can't they??

[Malcolm Needs ☆]

Our IRL uses tube(they love tube) and do not use gel unless you specify or if they are not able to demonstrate any reactivity @ PEGAGT, @ Enzyme AGT with same specimen...THat is the reason we try not to send specimen which are too week...as they come bcak with non reactive. Our IRL wants to stick to tube eventhough they have lots of clients who uses gel. I do not know why?? I know one reason tehy gave me was they can not DTT treat or CHloroquin treat teh cells...they can validate??? can't they??

That is an excuse; not a reason.

We Use DTT and Chloroquine and use gel with no problem whatsoever.

:mad:

[mcgouc]

While I was off a few days, the techs sent an antibody to our reference lab without really looking at the panel they had performed. When I reviewed our gel panel it was a perfect anti-Jka. The reference lab uses LISS and PEG. They told the techs the patient had an anti-Jka and an auto anti-M. The techs told them to crossmatch and send compatible blood. When I asked the techs why they had them crossmatch and send Jka negative units, they said they thought the auto anti-M would make the crossmatch incompatible. It took 12 hours and a lot of money to get 4 units of Jka negative blood. If the techs had looked at our panel, we would have had crossmatch compatible, Jka negative blood for the patient within 2 hours of completing the panel - and we would have saved a lot of money. If the reference lab had used gel, they would have only seen the anti-Jka and would have completed the work-up faster. We would not have known the patient had an auto anti-M, but that had no significance for our treatment of the patient.

[L106]

Hmm..... I've never seen an Auto-Anti-M. Have many of the rest of you? (Just curious.)

[Malcolm Needs ☆]

Hmm..... I've never seen an Auto-Anti-M. Have many of the rest of you? (Just curious.)

Yes, sorry, but we identify quite a few every year.

:redface:

[David Saikin]

I have seen a few (and 2 in the past 2 weeks but one was previously id'd with tubes). Once we see an anti-M in gel we immediately switch to LISS tubes. I know it is significantly less sensitive but I need to cut through the M and see if there is anything else hiding. I don't use PeG to f/u gel anti-M's unless my LISS results appear spurious.

[BSIPHERD]

Hmm..... I've never seen an Auto-Anti-M. Have many of the rest of you? (Just curious.)

We occasionally see what appears to be Anti-M in an M positive person. When we see them we report an Anti-M with the following comment:

Anti-M may occur in patients who are M positive. Most of these are autoantibodies, although some appear to be alloimmune in nature. If transfusion is necessary, compatibility may be determined by random crossmatching of appropriate units. 22% of donors would be expected to be M negative.

[L106]

Thanks, Malcolm & David. Interesting! Would I be correct to guess that most of these cases of Auto-Anti-M react best at room temperature and colder and are usually not clinically significant? (This site is like access to a panel of international experts!) Thanks!

Donna

[Malcolm Needs ☆]

As far as the examples I've seen, yes you would be perfectly correct (except that you do pick them up in DiaMed gel IAT, because the plasma and the red cells are together for a brief time at room temperature before incubation at 37oC; but long enough for sensitization to take place).

[mcgouc]

I have seen several auto anti-M's and found some using gel. However, gel didn't pick up the one that was with the anti-Jka we sent to the Reference lab. If we don't find any clinically significant antibodies with an auto anti-M, we just give crossmatch compatible.

[GilTphoto]

We only use tube method. About 90% of the anti-M's we see are very strong and don't prewarm away. I have seen a few autoanti M's too.

[Lindz82]

i work in a reference lab ( though not yet an IRL). Two things... 1. As a refernce lab it is our job and duty to identify and specify ALL antibodies in a specimen. That is the reason it is sent to us. So we use both gel and tubes. Test at 37 degrees and RT and cold if needed. We are providing the most complete picture we can for the client hospital. 2. Why in the world would you wnat to send out a specimen to a reference lab that could not even repeat the reactivity you see!! That souds nutty to me. ... I guess I have three things...3. i have personally seen up to a 2+ differennce in sensitivity between gel and PEG or LISS. That means a 2+ SIGNIFICANT antibody could be missed if only using tubes! I know that there is some extra pain in the rear reactions in gel... but isn't it worth it for the sensitivity that could help the patient!

[Malcolm Needs ☆]

i work in a reference lab ( though not yet an IRL). Two things... 1. As a refernce lab it is our job and duty to identify and specify ALL antibodies in a specimen. That is the reason it is sent to us. So we use both gel and tubes. Test at 37 degrees and RT and cold if needed. We are providing the most complete picture we can for the client hospital. 2. Why in the world would you wnat to send out a specimen to a reference lab that could not even repeat the reactivity you see!! That souds nutty to me. ... I guess I have three things...3. i have personally seen up to a 2+ differennce in sensitivity between gel and PEG or LISS. That means a 2+ SIGNIFICANT antibody could be missed if only using tubes! I know that there is some extra pain in the rear reactions in gel... but isn't it worth it for the sensitivity that could help the patient!

I think that you have to be careful here Lindz82.

I agree that it is the duty of the Reference Laboratory to identify and specify all clinically significant atypical alloantibodies against the major blood group antigens in a sample (and, if you happen to detect a clinically insignificant atypical allo or auto-antibody, those too should be reported, together with advice for cross-matching, transfusion and/or HDNF). In certain circumstances, it is also our duty to identify and specify antibodies against the more minor blood group antigens.

Where I differ from you (and this may be semantics, but it is important) is that it is your job and duty to identify and specify ALL antibodies in a specimen. Unless you have an unlimited supply or reagent red cells, you are never going to do this. Indeed, in the UK, screening and panel cells are tested to ensure that they are Wr(a-), because anti-Wra is quite common, whereas the Wr(a) antigen is very rare. The same applies to many low fequency antigens.

This is why we NEVER report that "No additional antibodies were present", but ALWAYS "No additional antibodies were detected."

As I say, this may be semantics, but it is an important legal point.

:cool:

[Lindz82]

Yes Malcom... I agree. The specific point I was getting at was the cold auto. If we see the reactions we HAVE to at least attempt to ID it.

[Malcolm Needs ☆]

Yes Malcom... I agree. The specific point I was getting at was the cold auto. If we see the reactions we HAVE to at least attempt to ID it.

To a certain extent I agree.

If it is a strictly "cold" reacting antibody that looks like an alloantibody, we would make a token gesture, but we wouldn't work for hours on it if we couldn't do it in one pass.

If it is a strictly "cold" reacting antibody that is obviously an auto-antibody, we wouldn't bother. Even if it were a case of CHAD, the specificity is neither here nor there (e.g. does it matter if it is an anti-I or an anti-HI? We are not going to provide the patient with adult ii units).

Even in cases of PCH, it is very unusual to have to provide pp blood, especially as the condition is often transient (although, of course, there are exceptions when the patient is in extremis and pp is required).

[Lindz82]

That is just policy for us... I am still a newbie so I am quickly learning no two places are the same. (It also means I don't heve much say in policy... yet:tongue:)

[klsutherland80]

I have seen an auto anti-M which reacted very strongly only at AHG; no reaction at I.S. or 37 C.

I have also seen 2 other strong IgG anti-M antibodies.

[John Eggington]

We do, sometimes, encounter anti-M in patients who type as M+. I'm not convinced they are all truely auto antibodies, but that's what we call them. The most recent patient set they appeared amongst were very young 'cardiac' patients, so I wonder if it's something to do with treatment/pre-conditioning (a bit like the 'dialysis' anti-N that we used to see).

[hunb]

I have an example of an anti-M that is being monitored in a maternal patient for antibody titration. Since there is a collective wealth of knowledge here I figured there would be somebody with an answer. The father is an M-positive individual and the patient has had three titers performed now, the first in October was anti-M reactive at AHG - titer of 1:8, the second titer was 1:1 - AHG, the titer performed this month was again 1:8 at AHG but had an IgM component reactive at room temperature at a 1:2 titer. My question pertains to the significance of the titer results, is the mother considered a high risk pregnancy now that both antibody types are present in her sample? Also, what woud be considered a significant rise in titer in this patient, In my limited knowledge I have the understanding that the titer should have doubled to be considered significant, is this correct in relation to anti-M?

Many thanks