MTS Gel screen/panel result controversy

[silverblood]

At our hospital we us the Ortho MTS Gel system for our antobody screens (3 cell) and antibody identification panels. Occasionally, we will have the experience of having an antibody screen that is positive but when we proceed with the antibody identification panel results are either all negative or inconclusive. Some techs here feel that in this case the antibody screen should still be reported out as positive and the antibody identification (of course only after having done all rule-outs-correctly I hope!) should be reported out as 'all clinically significant antibodies were ruled out' Others feel that in this case the negative/inconclusive panel result should be followed up by a tube screen. If the tube screen result is negative the antibody screen would then be resulted out simply as negative-of course specifying that the manual tube method was used. Of course, if the tube screen result was positive then further investigation would be needed. I have had numerous calls from physicians who do not seem to understand what the term 'all clinically antibodies ruled out' means-if an antibody screen is resulted as positive they want to see a spcific antibody result. I have seen some even cancel scheduled surgeries as they feel this indicates a questionable report. This has been a subject of controversy at our hospital for some time now-I would appreciate some input from others as to how this would be handled.

[tbostock]

We report the antibody screen as positive. If there are no reactions at all in the panel, and we suspect a false pos in the screen, we result the panel as negative. If the panel shows up with some weak positives that don't match anything, and everything is properly ruled out, we report it as "clinically significant antibodies ruled out".

[PAWHITTECAR]

We report the hold the screen result until the panel is complete. It the panel is all negative the screen is repeated in Gel again and is still positive or if the panel has random positives and everything rules out we result the screen as positive and the panel as "Patient exhibits a non identified AHG reacting antibody."

[rmblack]

Anti-E (in low titers) is notorius for not showing up on Panel A from the Ortho MTS products. I have our techs perform panel B when Panel A is negative. I can't explain it but Panel B seems to be a little more sensitive for Anti-E. Just something to think about. If Panel B is negative I would repeat the screen in gel with either a new lot (be cognizant of the possibility of rare antibodies and the antigen pattern) or try fresh screening cells of the same lot.

I would be careful of running an antibody screen in tube then calling the antibody screen negative. In my comparison studies tube is 1+ to 2+ less sensitive than the Gel methodology, which is why you sometimes pick up stuff that seems impossible to identify. When that happens, we call it a "Miscellaneous Antibody" and make an external comment to the effect that "All clinically significant allo-antibodies have been ruled out. Units are crossmatch compatible at AHG and Immediate Spin phases". I've never had a physician call me yet reporting it like this. They ultimately want to know if they can have compatible blood if they need it.

[SMILLER]

Unless we can get a negative screen with our other method (tube), we would report out the screen as positve. A negative AB panel would the be reported out as equivocal. (In fact even if a few cells are positive on the panels, as long as we get all of our rule-outs, the AB "ID" is reported out as equivocal.)

All units crossmatched for an equivocal AB patient are carried through AHG.

Scott

[silverblood]

We've been aware of the anti-E issue for some time now. If we suspect anti-E becuase of the pattern in the screen or if a patient is already known to have anti-E we will incubate the panel longer (instead of 15 min. we will take it to 30 mins.) Also, it'smy understanding that panel B is more specific for the Rh antibodies. NOt sure our Drs. would like 'miscellaneous antibody' either-new medical director is coming soon who will hopefully help solve some of these issues for us. Sounds like we may just need to standardize our method of reporting.

[OxyApos]

We use the Echo but sometimes experience the same phenomenon. We call it a Non ID AHG just so we will perform Coombs crossmatches. Our doctors don't seem concerned as long as there's compatible red cells. Remember how sensitive Gel and Capture methods are...these could be all sorts of low titer antibodies or non specific reactions that weren't detected in the days of tube only. I do look carefully at the cells on the screen and panel that are homozygous for E and honor that if there's a question.

[adiescast]

If the panel is negative, we repeat the screen in gel and tube. If the gel is still positive and the tube is negative, we call the antibody "Coombs reactive antibody of undetermined specificity by gel only." If the tube is positive, we also run a tube panel. If the tube panel doesn't show a specificity, we call it "Coombs reactive antibody of undetermined specificity." This designation requires a Coombs crossmatch.

[Likewine99]

We do the same as Terri and have our computer system set up to require an IS and a gel xm. I agree with rmblack about doing a tube screen and if neg calling the absc neg.

[ElinF]

We would repeat the screen and panel in gel. If still reacting funny we would check for cold reacting antibodies in tube by doing a IS and 4 C incubation. If it is a cold, we report as such. If it miscellaneus reactivity we report the usual phrase "All clinically significant Antibodies ruled out"- after they have been ruled out of course.

[tkakin]

We do not report the screen until the panel is complete as well. If Panel neg and tube screen negative we report negtive. If strong inconclusive reactivity, we report Inconclusive.

I do like the idea that the Dr.'s are questioning the results. I was thinking they didn't even read the reports . I don't have the resources to work up inconclusive reactivity, so I would give them the option of sending it out to a reference lab with the side note of cost.

Edited February 17, 2013 by tkakin

[kirkaw]

I am curious about the tube method folks are using as a follow-up when your gel antibody screen is positive and gel antibody panel is negative. Do you use enhancement; if so what kind?

We have these same phenomena at hour hospital. I have seen it occur with screening cells that are getting old and could possibly be contaminated. So I have techs re-run the antibody screen with fresh screening cells (same lot # if we have it) and if negative, then we call the antibody screen negative. If it is still positive, we say 'positive antibody screen, negative panel; issue Coombs crossmatch compatible red cells.'

[Mabel Adams]

We would use a 3 cell PEG screen in this situation to more closely approximate the sensitivity of gel.