gel vs. tube...Warm autos...

[labgirl153]

Situation for which I need input:

My small lab uses the Ortho gel methodology, When we encounter positive reactions with all 0.8% screening and panel cells in gel (including auto and DAT), we then run a panel (Immucor) in tube (LISS) to compare results before sending out to ARC ref lab.

Sure, gel is more likely to pick up warm autoimmunes than the tube method, but if the LISS panel is negative and we send out to ARC, they can't duplicate our + gel results because they use the tube method exclusively. Because of this, we go with the negative tube method results and perform full x-matches in tube. If the patient hasn't been transfused in the previous three months, we get a meds list, determine what the likely culprit is and document it. If recently transfused, we perform an acid elution (in tube with LISS) and run against a panel to ensure no alloantibodies are showing up. This works fine and our patients have no problems.

However...we have a new tech whose experience from elsewhere has her perform the elution in gel and if all cells are positive in gel just as the initial workup was positive, she documents this as a warm auto with no specificity, regardless of how the tube method comes out. (And at her former workplace they performed their own adsorptions).

If the ARC holds to the tube method as their standard (at least in my region), then this might tell me one of two things:

a) If it doesn't demonstrate in tube, then it's not a big deal.

If a patient's plasma is consistently positive in gel but is negative with another method, then isn't it possible that the patient is reacting to something intrinsic to the gel method (antibiotics, preservatives, the gel matrix etc.) and that the positive DAT (via tube method) is more likely to be simply drug-related and not a bona fide warm autoimmune antibody...or at least not a significant one?

I've not seen much on this subject elsewhere, and I'd like to read what others have to say who are experienced in using gel methodology.

[donellda]

I used gel for several years when I worked at another location and it is very sensitive. Warm autos are often LISS sensitive so maybe the gel is just that sensitive to pick up a weak warm auto that will not react with a LISS tube method. We used to use a 30 minute incubation tube method without LISS for our warm autos and often times we were successful in getting negative reactions and finding compatible units with having to go to absorption techniques. I do remember trying our eluates with gel but if I remember correctly we abandoned the idea very quickly.

[labgirl153]

I like the gel methodology...don't get me wrong...but because of the increased sensitivity, I wonder if it's picking up warm autos that have little significance clinically.

Didn't mention previously too, that this new tech also will "call" it a warm auto even though several cells in the straight gel panel are negative. Thisi s because often, even with negative cell reactions, the eluate in the gel will test as positive with all cells, so she feels justified calling it a warm. I don't concur with her thinking on this however. If there are negative cells in the initial panel/screen then it's likely to be something else...and we know from studies that many of the "non-pattern" scenarios in gel are a result of anti-Bg in the patient (especially females). I've never seen a warm auto that wasn't uniformly positive in all cells, both the initial panel/screen and the eluate.

...Which leads us to what you noted Donna...your facility gave up elutions in gel...and I believe probably for the same reason that I normally don't use gel for elutions...in more cases than not, the cells all pop up as positive with no specificity. I believe there's something more going on with the gel matrix or some other factor inherent to the gel that might make it problematic to use routinely in elution testing.

[David Saikin]

I think that your new tech needs to follow your protocol. You do have a protocol, yes? If you do, then you must have a reason for having it . . . the tech needs to comply. Or - you can do it your new tech's way. By allowing this current process to continue, you are sending conflicting and possibly confusing information to your Medical staff.

[labgirl153]

Yes David, I'll promptly go spank her now. Really now.

I agree that she needs to follow protocol (yeah, we have one), and I'm not happy about her performance, but that's my super's problem and not mine. I merely added the info about her "technique" as a complication to the gel method alongside the tube method. Basically, I'm looking at the factors inherent to the gel method that can create inconsistencies. I'm looking for techs to give input on their experience with gel...not lessons on how to get my co-worker to do her job.

[Cathy]

Back to your question about the patient plasma reacting to something within the gel system. We believe we have had two patients recently reacting to something (antibiotic, preservative?) in the 0.8% suspended cells. Both scenarios were identical. Positive antibody screen, (all three cells); gel panel all positive except for the autocontrol. We diluted 3% screening and panel cells with the MTS diluent, all were negative. Gel crossmatches were all fine as well.

If we suspect a warm auto we go to LISS. If we can rule the clinically significant antibodies, we use crossmatch compatible units.

[labgirl153]

Thanks Cathy...suspected there were people out there who'd seen this problem with gel before as well but until I'd read of their accounts for myself, I couldn't prove it to anyone else.

Like your lab, we go to the LISS, and I see, you reduce the 3% immucor cells to 0.8% and then run them in gel, so that proves it's not the gel itself, rather the 0.8% Ortho cells, i.e. the antibiotics/preservatives or processing as you noted. And normally, our autocontrols are negative and the x-matches compatible, so again, it's not the gel matrix, rather the ortho cells themselves. If I recall correctly, the MTS diluent has the same antibiotics as the 0.8% cells but the MTS insert doesn't list the concentrations of the antibiotics, whereas the insert for the 0.8% cells does. So it might not be the antibiotics, rather, some other difference unknown from the info we get in the inserts.

[BSIPHERD]

We use PeG, not gel, but the situation is the same. We would do a panel and an eluate using PeG. If the patient had a positive DAT and all cells were positive in both plasma (and eluate), we do a LISS screen. If the LISS screen is negative, we report a PeG reactive Warm Autoantibody, and we crossmatches by LISS technique. If the LISS screen was positive, we'd go to warm auto or differential adsorption.

[feliciat]

Does anyone drop all enhancement (PEG, GEL, enzyme) and then test for underlying ABY?

[Likewine99]

We use gel as our primary tool, LISS as our secondary and "no enhancement" as our third. We have several patients that react with all panel cells in gel that often show neg rxns or no clear cut antibody pattern with LISS or no enhancement.

We report this as "all common clinically significant antibodies ruled out" and add to our BB system an internal free text comment of "perform non-gel complete crossmatch procedure to obtain compatilble units".

[PBryant]

We routinely screen using both LISS and gel methods and perform a DAT by tube method.

Recently we had been asked by a customer to perform the autocontrol in Gel so as to duplicate their results. Our tube DAT was negative----and usually will be unless the autocontrol in Gel is strongly positive (3+ or more). Our tech performed a DAT in Gel (1+) and by tube (negative). An eluate, tested by tube method, was negative. Out of curiousity we then performed an eluate in Gel and it was also negative. Routinely we do not perform eluates in gel.

The patient did have an alloantibody (Lea) and units were crossmatched using the gel IgG card.

I tend to agree with the thinking that the gel system is too sensitive to give clinically meaningful DAT reactions at 1-2+.

[rescyth]

in clinical terms, sensitivity is called as the TRUE POSITIVE and specificity is True NEGATIVE. If you increased the sensi/speci too much, it will give you false results... -just my 2 cents

Edited March 16, 2009 by rescyth
too sleepy -_-! got to get out of 3rd shift...

[Trek Tech]

When you dilute the 3% cells are they from Immucor? I had the same situation this weekend and I diluted my Ortho 3% cells to 0.8% and still had panagglutination (the auto was negative). I sent it to my reference lab and they diluted Immucor 3% to 0.8% and ran in gel and had all negative reactions. I called Ortho technical service and they told me to try washing the 3% Ortho cells 3 or 4 times before making the 0.8%.

We are a small physician's office lab blood bank and I don't have the capital to purchase from 2 vendors. Each time this patient (actually there are 2 of them) comes in I have to send them to my reference lab. This is very costly. I love gel but sometimes it causes me grief.

There were no underlying allo's (Crossmatches were performed in gel and were negative at the reference lab)

Edited March 17, 2009 by Trek Tech
Forgot reference results

[jayinsat]

Labgirl, I think the question thant needs to be asked if what the new tech is doing is causing harm. I realize that there is a discrepancy between you two as to how best to work up these situations, however, in blood banking, there are often several routes that can be taken in complex antibody identification. Perhaps your new tech has found specificity on the elutions despite negative liss reactions on tube in the past. Is there harm (outside of cost) in doing the extra testing, or even calling it a warm? What if an autoadsorptions does allow an underlying allo to show itself? Yes, in most cases she is probably chasing a rabit trail but her experiences may show her the importance of chasing those trails so she can rest at night knowing that she gave the best product for the patient. I don't think it's ever a good idea to supress someone for going above and beyond. Yet she should have the right attitude and not be arrogant in her approach.

Just thought we should look at it from a different perspective.

[ChrisH]

I had the same situation this weekend and I diluted my Ortho 3% cells to 0.8% and still had panagglutination (the auto was negative).

It could be something to do with what Ortho uses and Immunor does not. I would agree with what Ortho says, by washing the cells you get the preservative off and you are only testing cells and patient serum/plasma. I have seen an number of Anti-Ortho's (our inside joke).

[Mary**]

Cute antibody!!

[schorj]

About six months ago we switched from manual gel testing to the Immucor ECHO automated solid phase testing. We are a large reference medical center and we get a lot of warm auto patients. In every case, so far, if the ECHO results showed a warm auto pattern, we would get the same reactions if we tested with tube reagents. We also used to see the same "false positive" reactions with the manual gel testing, that are described in the above postings. We have only seen a couple of "false positives" with the solid phase testing, where the tube testing would be negative.

[janet]

It could be something to do with what Ortho uses and Immunor does not. I would agree with what Ortho says, by washing the cells you get the preservative off and you are only testing cells and patient serum/plasma. I have seen an number of Anti-Ortho's (our inside joke).

The clue to these usually is a negative reaction with the auto and any units crossed (anything NOT in their preservative) .... I always try washed screening cells when I see those clues!

[sdweaver29]

I am really pleased to see that other techs are seen the same problems in reference to WARM autoantibodies. I think we may be getting to comfortable calling things WARM and the gel technology seems to have created a lot of confusion.

Our facility follows similar protocols as you have described.

[BankerGirl]

Does anyone have problems with gel giving mixed field reactions on their eluates? We have just begun using gel and are trying to correlate the eluate testing. We have run into a few samples that test fine in tube but show mixed field reactions in gel. The truly positive cells seem show clear positive reactions in the gel, it is the ones that should be negative that are a problem (i.e., solid line on top of the gel and a cell button on the bottom).

Thanks!

[Yanxia]

Is it the destroyed cells in the eluate?

[BankerGirl]

I don't believe so, since it is not evident on the positive cells, and we do centrifuge the eluate quite well.

[KKidd]

We have seen instances lately where all cells were positive in gel, including the auto. THe DAT was negative by tube. We added 50 ul of the 0.8% pt suspension to a gel solumn and spun it(no plasma). IT was negative. Tube abscreen - neg. I'm thinking reacting with the tesing materials. The funny hting is this has been more prevalent since allergy season started. A coincidence?

Are you getting very weak non-specific reactions? I started calling it "Funky Junk" or maybe a new classification Anti-fuju. THe joys of Blood Banking!!!!

[BankerGirl]

YES! we get a few weak non-specific reactions a week. I love the Anti-fuju!!

[Cathy]

BankerGirl, Do you pour off your eluates when you spin them? I recommend spinning a couple of times, (pouring off into a fresh tube each time). You may see brown crud (red cell stroma maybe?) left in the original tube after the pour off. I never see mixed field reactions anymore with eluates.