Does anyone utilize flowcharts to assist with TANGO antibody issues that do not make sense and would be willing to share?  My facility is fairly new with the TANGO.

3 patients recently that have had positive TANGO antibody screens (one with one cell 2+; one with 2 screening cells-2+; one with all 3 screening cells 2+). TANGO panels (panel I-8 and panel 11+) on first 2 patients were negative. TANGO panel (I-8) on the third patient reacted 2+ with 5 out of 8 cells---no specificity.  Crossmatches on all patients were compatible by TANGO and manual tube using LISS.

I am leaning to the fact that if manual tube testing (still the gold standard) is negative and units are compatible, the TANGO reactivity is non-specific.

 

Our facility is strongly considering switching to the TANGO due to the high number of unexpected positive reactions we see on the ECHO.  To now read that you are having similar issues with the TANGO unnerves me.  I'm wondering if Solid Phase is in itself overly sensitive.

The decision was made (among others) to go with TANGO solid phase because this method had much less unexpected reactions than the ECHO. We did expect "unexpected" reactivity to occur with the solid phase method. Unfortunately, there is no resolution with these patients, so far.

Does anyone utilize flowcharts to assist with TANGO antibody issues that do not make sense and would be willing to share?  My facility is fairly new with the TANGO.

3 patients recently that have had positive TANGO antibody screens (one with one cell 2+; one with 2 screening cells-2+; one with all 3 screening cells 2+). TANGO panels (panel I-8 and panel 11+) on first 2 patients were negative. TANGO panel (I-8) on the third patient reacted 2+ with 5 out of 8 cells---no specificity.  Crossmatches on all patients were compatible by TANGO and manual tube using LISS.

I am leaning to the fact that if manual tube testing (still the gold standard) is negative and units are compatible, the TANGO reactivity is non-specific.

I have been using the Tango for about 3 years and I really like it. Just recently, we are experiencing what Susan is. I have spoken with Tech Support and they are working on it. It is not at all the norm. We rarely if ever got false positives. Compared to Echo users that I know, this is not even close. Our procedure now, when the panel comes up negative is to run the Tango screen again and/or the gel screen to compare. If negative, we're done.

Although yes, tube testing is the "gold standard", it is MUCH less sensitive than solid phase and many clinically significant antibodies may not be detected in tube if they are only reacting 1+ in solid phase. We find gel to be more comparable in sensitivity so that's what we use to troublshoot.

Susan: not sure if you want to work on flowsheets just yet, as BioRad is working on resolving this, and they hope that the next lot number of screening cells may not have this issue.

I would just query how "clinically significant" are the antibodies you are missing that are being detected by solid phase, but not by other techniques Terri.  As I have said many times on this site, I cannot remember us killing too many patients when we only had tube techniques, before the days of gel and solid phase.  It could be that we are detecting them earlier "in their life", but just how "clinically significant" are these antibodies?

Thanks for the insight. I was also contacted by tech support and can't wait until this lot number for the screening cells is done!

I would just query how "clinically significant" are the antibodies you are missing that are being detected by solid phase, but not by other techniques Terri.  As I have said many times on this site, I cannot remember us killing too many patients when we only had tube techniques, before the days of gel and solid phase.  It could be that we are detecting them earlier "in their life", but just how "clinically significant" are these antibodies?

Yup, you're correct Malcolm. Not sure, especially with the Anti E that we detect very weakly in gel and solid phase, but not at all in tube method, if these even "matter". But we humor them anyway.

I can say that with our volume that I'm glad that tube testing isn't our only method.

The new lot was released last week, to be recieved no later than Friday. Did you not start the new lot early? I understand Bio-Rad will provide additional screening cells If you choose to start this new lot early and run short before expiration.

Over the years, tube testing antibody screen has changed significantly: eliminating room temperature incubation (just immediate-spin), then doing away with immediate-spin, eliminating the saline tube and doing 37C Albumin, switching from Antihuman Globulin to Anti-IgG antiserum, then dropping albumin in favor or LISS, reducing incubation time from 30 minutes in albumin to 15 minutes in LISS. 

 

So when I hear about tube testing being the "Gold Standard", I ask, "Which flavor of antibody screen is it?".  4-tubes, 2-tubes, two-cell screen, 3-cell screen, 4-cell screen,  immediate-spin and room temperature/both or neither, Saline and Albumin, Saline only, Albumin only, 37C-to-Antiglobulin only, LISS-suspended cells, LISS-additive, PEG?  How many varieties did I miss?  Tube Testing was a journey, not a Gold Standard.

To add onto what Malcolm stated as well - if we get unexpected reactivity in one method - we do use another method just to be sure - and if there is nothing there we usually monitor the patient with AHG XMs until the screen goes back to negative. We don't try to "chase something down" that isn't there or isn't "clinically significant."  For example, we know we see more Jka's on echo that don't show up in other methods, but I am happy to identify them - the old philosophy "pay me now or pay me later," but we do see nonspecific reactivity. We've used manual gel, PeG, LISS, solid phase (echos) - and gel and echo seem to both have their issues with nonspecific reactivity but I do love when they "find the antibody first." I will also say that we treat our echos as AUTOMATION (not as a tech) everything goes on them; they are the first TOOL to do our workups, so we set our expectations to still do complex workups by bench.  I couldn't imagine life without them. (we are a big hospital with lots of prenatals) However, when a complex antibody comes up or a screen is pos but the panel is unexplained or panagglutinin - we refer back to another method, and move on with life. I also don't believe in a "gold standard" in blood banking - everything is a tool to help aide in patient care (and safety).
I think whatever method you choose to do primarily it is nice to have a flow chart or two - but of course they are not going to catch every scenario and there will always be exceptions. I'll try to get an attachment on here if I can! Nice thread!