Study finds Igenex has a 57.5% FALSE positive rate - I'm horrified!

Daffodil

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@Daffodil - I have also read that late stage/chronic lyme patients have impaired antibody production which may make testing antibody response more challenging. However, my understanding is that this has no bearing on FALSE POSITIVES, which is the concern being presented in this thread.

Yes, I also wish the sample size was larger, but anything over 30 is worthwhile. And certainly with such a large error rate, this is most worthy of publication. Further, this part of the study (specificity/false positives) is fairly straightforward, and unless their is some grossly negligent sampling or selection bias, the results are provocative ... and disturbing.
oh yea. I guess not making antibodies wouldn't affect a false positive hehe sorry
 
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Ok I see it now. Yes, their response is a little unsettling. To me it sounded like, "Well 3 controls we didn't have enough blood to redo, so we threw them out" "A few more that we said were positive were actually negative" "After we redid the rest, more negatives" .
@Belbyr
I agree! And the fact that they're even retesting at all - is an inappropriate response. They can retest all they want after the fact, it doesn't change what the actual results of the study are...it doesn't take back the false positives for the 23 healthy volunteers at the time of testing.

And then this... "when using revised interpretation criteria and recombinant antigen WB, demonstrates a specificity of 91.7%" -- Are they now using revised criteria? Are they now using recombinant antigen WB (a new method) for doing the WB? Was this done just for retesting? Is this the new Igenex standard? And even if they some how get down to only 2 false positives, what denominator are they using to get a 91.7% specificity. It's not 37. This paragraph is incomprehensible. It is the crux of the response, it should be spelled out clearly. Are they being intentionally vague?! Besides the fact that the rest of their response is ridiculous, more self aggrandizement and marketing. I can go on and on. It's disturbing.

By the way, I'm sorry to read about your experience. And how interesting that you witnessed first hand, healthy people testing positive thru igenex. I actually want to send me healthy neighbor for testing to see what comes back! But, I'll be damned if I give Igenex another dime.

@Valentijn - Unfortuntately, the Lab Specialty B is definitely Igenex. When going through the article, they describe the testing that Lab Specialty B does and it matches exactly to Igenex. Further, Igenex responded to this. Igenex is not responding to false positive put out by another lab...it's their lab. And hope the above answers your question on my opinion of the igenex response.
 
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TrixieStix

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@Belbyr
I agree! They can retest all they want after the fact, it doesn't change what the actual results of the study are...it doesn't take back the false positives for the 23 healthy volunteers at the time of testing.
Is it possible the false positives via Igenex in the healthy controls was due to the fact that Igenex's old criteria allowed for an "Igenex positive" test with only bands that are known to cross-react with common antibodies that the healthy controls likely did have like EBV? And thus when Igenex changed their criteria a person could no longer be "Igenex positive" without having Lyme specific bands??

Also in the Fallon study when they say "false positive" are they talking about Lyme specific bands showing up in the healthy controls and creating a false "CDC positive" or that the healthy controls were deemed "Igenex positive"?
 
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So if one is going to talk about being "misled" it may be good to understand there are two sides to that coinage.
@duncan - I'm afraid I disagree. Igenex has been purporting very high specificity rates -- and the Brian Fallon study blows that out of the water. This post is about the Brian Fallon study, and their findings of an outrageously high false positive result from Igenex. This is not a post rehashing the lyme controversy or the general shortcomings of testing. Igenex has been claiming something, that now appears to be independently tested, and proven false. I most certainly feel misled.

One is that this is in great measure a market conflict. Yes? This is about markets and market competitors in contention. The 2008 (?) suit levied against the IDSA Guidelines reflected that in part, I think.
This is not about market competition, it's about science. The specificity rate of a diagnostic can be tested and calculated. And whether it was tested correctly, calculated correctly, and advertised correctly by Igenex -- is what this post is about.

Second, some companies possibly serve a purpose in disputing the controversial narrative put forth by a couple of dogmatic agencies that Borreliosis is a little more than a nuisance disease. Many Lyme advocates feel - right or wrongly - that IgeneX is one of those companies. That this is an important conversation has little controversy.
That's fine, but if they are misrepresenting the specificity of their testing, it's a major problem.

Third, there appear to be some appealing elements to IgeneX diagnostic offerings, including that they don't simply test the B31 strain - they use at least two. Also, they include one other virtually Lyme-specific band (or is it two?) the 2T does not -- these bands were removed from the usual WB due to the Lyme vaccine introduced 15 or so years back...but the bands are very Borrelia-specific.
Both Stonybrook and MDL will report out a 31 band.

If in fact Brian Fallon's results are true, and that half of the normal healthy population will test positive for Lyme through Igenex, then this far outweighs any "appealing elements" - imo.
 
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Is it possible the false positives via Igenex in the healthy controls was due to the fact that Igenex's old criteria allowed for an "Igenex positive" test with only bands that are known to cross-react with common antibodies that the healthy controls likely did have like EBV? And thus when Igenex changed their criteria a person could no longer be "Igenex positive" without having Lyme specific bands??

Also in the Fallon study when they say "false positive" are they talking about Lyme specific bands showing up in the healthy controls and creating a false "CDC positive" or that the healthy controls were deemed "Igenex positive"?
@TrixieStix - It's most certainly possible that in response to the Fallon study, they have changed their interpretation criteria and/or methodology -- to reduce these false positives. If I were Brian Fallon and found this in one of my studies, I would send it straight to the regulatory agencies for investigation. Given what Igenex was claiming, to find these results among medically healthy controls, is absolutely outrageous (imho).

Unfortunately, the Igenex response is so cryptic, it's hard to know what's going on. Hopefully, they've improved their testing, out of good will, or fear of a regulatory investigations. (Whatever it takes!)

And I'm hoping other PR members may have additional information to share on this subject, particularly, what (if any) changes Igenex has made....which can put all of our minds at ease.

To address your second question, Table 2 shows multiple rows. For example, the 23/40 (57.5%) false positive rate is for the WB IgM or WB IgG (laboratory criteria). For WB IgM or WB IgG (CDC criteria), the Igenex false positive rate is 10/40 (25%). And for just WB IgM (CDC criteria), the Igenex false positive rate is 8/40 (20%). There is a row for each, including the Elisa and also 2-tier testing schemes.

Igenex isn't the only lab shown either. There are 4 columns, one for each lab. Hope this helps!
 
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valentinelynx

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Table 2 shows the false positives, and "Specialty Lab B" is Igenex.
Hey, folks, why are people ignoring @Valentijn's comment?

This study doesn't mention Igenex at all. Igenex requested that the authors of the study send them the samples which were sent to Lab B for analysis. There's no indication in Igenex's response that they are Lab B.
This seems to me to make the entire anti-Igenex argument being promulgated here moot. Unless someone knows for sure that @Valentijn is incorrect? (Which she generally isn't...)
 

duncan

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Igenex has been purporting very high specificity rates -- and the Brian Fallon study blows that out of the water
Regardless of whether one wants to defend or support Fallon's results, this is old news, and your usage of tense appears to be in error. This is from 2014, and IgeneX reportedly retooled their protocol. Why disinter old news? Have I missed something?

This is not about market competition, it's about science.
Science, yes, but I would disagree with your declaration that it's not about market competition. See @barbc56 comment.

That's fine, but if they are misrepresenting the specificity of their testing, it's a major problem.
That's quite a leap from one dated study with a small sample size.

Both Stonybrook and MDL will report out a 31 band.
If Im not mistaken, IgeneX reports both bands omitted from the conventional WB due to the Lymerix vaccine, i.e. bands 31 and 34. Moreover, it measures against TWO stains, B31 and 297. This is getting more data into the hands of the patients. This is a good thing for many people.

If in fact Brian Fallon's results are true, and that half of the normal healthy population will test positive for Lyme through Igenex, then this far outweighs any "appealing elements" - imo.
BIG "if". And pretty much irrelevant if in fact IgeneX recalibrated its protocol.
 
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@duncan - The Igenex response on Pubmed was dated Nov 2015 - a little over a year ago. This is not my definition of "old news."

I agree and wish the sample size were larger too. However, as I mentioned previously, 40 subjects is decent, and there is no evidence to suggest any sampling or selection bias. Testing healthy volunteers is not rocket science. And when the Igenex results are returned, there is a paper trail. The results of the study ARE true, unless someone has a reason to believe otherwise?!

And most importantly, @duncan - If you know that igenex has retooled their protocol -- I would love more information. What changes were implemented and when exactly did this occur? Would greatly appreciate any documentation on this?? In fact, this is precisely why I made this post....
 
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@TrixieStix - THANK YOU so much for sharing. I haven't seen it, and haven't found any discussions on the Fallon study. I will read tonight when I have some extended time. Really appreciate your finding this!!
 

duncan

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@cyclist, the study that you were "horrified" about came out in Sept of 2014. And with all the news about persisters etc that has occurred in the interim, and developments both on the diagnostic fronts with direct antigen testing in the wings, and pulsed treatments and retooling of old drugs etc, and movements to legislate change in some states, this can be interpreted as old news.

A sample size of 40 against an annual population of over 300,000 in the US alone is hardly adequate. Indeed, much of the history of Lyme assessments, at least in the US, has been done with limited sample sizes, as the three RCTs sadly but amply demonstrate.

I do not use IgeneX, so I do not know the specifics of the protocol they are using now. You may wish to contact them directly - I have found them to be very helpful and open when I have contacted them. What I do know as a Lyme patient is that every data point I can garner that helps shed more light on the TBDs I harbor, helps me make better decisions.
 
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You responded with an assumption, and labeled it as a certainty. I still don't see how it could be considered certain, when Igenex isn't mentioned.
@Valentijn - In the publication, the authors describe Lab B to have an in-house WB using 2 different strains and the exact interpretation criteria that Igenex uses. Further, Igenex responded to the article in the pubmed commons sections. If you haven't seen this, it can be found underneath the abstract in pubmed before clicking through to the article. It was posted Nov 2015 and Raphael Stricker posted it on behalf of the Directors of Igenex, Harris and Shah. As part of their response, they discuss retesting the false positive samples.
 
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If Im not mistaken, IgeneX reports both bands omitted from the conventional WB due to the Lymerix vaccine, i.e. bands 31 and 34. Moreover, it measures against TWO stains, B31 and 297. This is getting more data into the hands of the patients. This is a good thing for many people.
Stonybrook and MDL also report 31 and 34.

At this point, their use of 2 strains is great self-marketing. It's unclear if their "unique methods" are really beneficial. Maybe it's a contributing factor to the horrible specificity found in Fallon's study.
 
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That's quite a leap from one dated study with a small sample size.
How do you explain how Igenex markets a greater than 97% specificity and Fallon found a 42.5 % specificity (i.e. 57.5 %false positives). I don't think it's a leap, it's the next logical thought.