XMRV Vip Inconclusive

[hensue]

I have a receipt where my test was run on Nov 24. Call Dr and no test.
Called VIPLab and they sent it on Nov 24.
Called again have not heard from VIP. VIP said my test was inconclusive?
was not positive or negative so Dr. Lombardi himself is running it again.
let you know when I get results.

What would you think?

I have chronic fatigue and fibromyalgia. Diagnosed at Emory Hospital in Atlanta over 10 years ago. A neurologist is the Dr who gave me the diagnosis.

 

[nora_n]

I read somewhere they were running a number of tests again. If not all. Probably why so few people have gotten any answer I think.

 

[Cort]

Maybe that is why. Interesting.....Love to hear more about this if anyone knows how a PCR test can be inconclusive. One reason I'm asking is that the Science study was unblinded - which I've been told was a problem with DeFreitas retrovirus study; once they blinded it - no one knew where a sample came from - her results tanked. That's not necessarily because the original test was unblinded - but it could apparently have played a role.

My question is how much subjectivity is there in interpreting these tests? I assumed they were all computer driven. Does anyone know?

 

[_Kim_]

I have a receipt where my test was run on Nov 24. Call Dr and no test.
Called VIPLab and they sent it on Nov 24.
Called again have not heard from VIP. VIP said my test was inconclusive?
was not positive or negative so Dr. Lombardi himself is running it again.
let you know when I get results.

What would you think?

I have chronic fatigue and fibromyalgia. Diagnosed at Emory Hospital in Atlanta over 10 years ago. A neurologist is the Dr who gave me the diagnosis.

Hi Hensue,

I'm sorry that this issue has extended your wait time. I never imagined that Dr. Lombardi would actually be doing bench work. In the lab that I interned in, the PIs almost never got their "hands dirty" anymore. Maybe a commercial lab is different.

Were you expecting a positive result?

 

[kurt]

To confirm our telephone conversation, your tests were inconclusive which means that virus could not be detected and could be conclusively negative either.

Dr. Lombardi is re-running the test.

That looks like a negative result.

But maybe they had low confidence in their result. I have been told this can happen when a particular blood sample is difficult to work with. So they sometimes have to take extra steps to extract what they need from the blood. If a test is negative, and the sample was difficult, that lowers their confidence in the outcome and a good lab will run those types of tests a second time.

Also, another possibility I have heard of is that if just one or two bands are positive on some tests, that suggests something is there but is not enough for a positive finding. So they need to narrow down if it is a false negative. Re-running the test helps that.

This is a very new and somewhat experimental test and this type of outcome, even having to re-run entire batches again, is to be expected.

 

[Katie]

I don't think any of us can tell you what it means, hopefully that them taking the extra time to do it again means that you get an accurate result whatever the outcome. It would be guess work from our point of view, but it's good to know they care about each and every result.

 

[Kati]

To confirm our telephone conversation, your tests were inconclusive which means that virus could not be detected and could be conclusively negative either.

Dr. Lombardi is re-running the test.

Inconclusive tests happen for some reason- for instance years ago I was inconclusive for Hep C- and when they re-did it it was negative. I think it was because my ANA is + which interfered with the test.

I am glad they are re-doing the test to ensure quality. Good luck.


ETA I phoned VIPDX to ask the status of my test kit order- they told me another 2 weeks wait (I was supposed to get it this week) It sounds like they are running low in supplies at the moment.

 

[imready]

Test results

I'm sorry to hear that your test came back Inconclusive. I never thought of that out come, that would frustrate me to no end. We wait so eagerly for out test result and to be told it's inconclusive and that they are going to re-run the test. Then what if they rerun the test and you are negative, I would still be wondering if that is the correct results and wondering if they should have asked for a new blood sample to re-run the test.

Did you order the package for both blood tests at $650. This is the package I ordered for my testing. I know that I would be banging my head against the wall if I paid $650 and the results came back inconclusive.

Don't let this stress you out, I know how hard it is to wait.

 

[Eric Johnson from I&I]

> Love to hear more about this if anyone knows how a PCR test can be inconclusive.

Cort, the basic way is to take the amplicon and run it out on a gel. How far it runs tells you the approximate length of the DNA, which had better be what you expected.

You visualize it by mixing it with ethidium bromide before you run it out. This binds to any and all DNA, and it fluoresces under UV light, letting you see how far your ampicon ran on the gel. You use an electrostatic field to make it run through the gel's pores.

Anyway, when you visualize it, it may be weak (dim). Then you wonder what the deal is. I guess there are probably other ways of doing this, but they may all read out using fluorescence -- if so, whatever the technique, the light may be weak, and then you start wondering.

 

[usedtobeperkytina]

don't

I don't know what it means, but when it comes to viruses, I don't think it is uncommon. I believe you can get false test results from HIV tests.

And pap smears, which check for possible beginnings of cervical cancer, supposedly caused by HPV virus, is not conclusive either. If you get a positive, they tell you to come back in a few months and they will run it again. Only two positives in a row will make them take action.

Tina

 

[Eric Johnson from I&I]

> How far it runs tells you the approximate length of the DNA, which had better be what you expected.

This is actually fairly exact, or close; it is not as approximate as I suggested. If it didnt run out about as far as it should, that would be a second thing that would make you wonder what the deal is.

 

[usedtobeperkytina]

It

From what I understand also, it isn't like if you have the virus it is all over the place, in most individuals. It may be they found some evidence of the virus but no virus. But looking for the virus is like looking for a needle in a haystack. They may look at 100 B cells and not see any of the virus. Then they look at B cell number 101, and there it is.

tina

 

[spit]

Cort -- I'm not an expert on PCR, but there are problems that can come up.

My understanding, and any better biochem folks can correct me where I will undoubtedly screw up:

In traditional PCR, the machine PCR portion of the work is basically just amplifying the amount of a target DNA sequence so that very small amounts of sample can give results, and without adding problematic isolation steps. The design of primers used, the set up of the experiment, and the analysis of the sample (traditionally, gel electrophoresis) are still done by people, with chances for error. In real time PCR, a machine does most of that analysis portion, but you still have to know how to set things up for your specific target, primers, dilution, etc.

Getting no or a very weak signal can mean that there's really no target (in this case, XMRV genetic material) in your sample, but it can also mean that something went wrong somewhere -- a primer with poor specificity, contamination, a mistake in the amounts of polymerase or other reagents, failure to program the machine to the proper heating and cooling timing for the specific target, bla bla bla. Real time PCR does a lot to try to counter these potential problems, but especially with a new and poorly understood virus, I'm sure the methods for this are still being refined, and inconclusive results can happen occasionally anyway, so far as I'm aware. Running it again carefully should clear things up, unless the sample itself is strange somehow.

Hope that helps a bit and that I'm not misremembering anything major.

 

[jenbooks]

Boy that must be so frustrating.

 

[valia]

I read it was like fishing, just because you caught no fish that day, doesn't mean there's no fish in river.

 

[spit]

hensue -- I'm not really knowledgeable enough here to even begin to guess about your sample, but I do know that with other work I've done in lab settings, things like teensy contamination from all sorts of stuff can make for some very screwy results. Lab folks try to be meticulous about that stuff and mostly do a very good job of it, but it's impossible to completely eliminate the possibility.

Sorry that your results aren't helpful at the moment. I hope they'll be able to get something more solid from another run. It would be pretty maddening to pay, send everything in, wait, and then get "inconclusive" as a result.

 

[Patient 2]

hensue, sorry you have to deal with this...hopefully lombardi can figure it out. good luck!

 

[misskoji]

Hensue

I'm sorry to hear of your inconclusive results. How frustrating that must be, I can imagine. I'm praying that you'll find an answer, a definative one at that, very soon. Thanks so much for keeping us updated though!

You're in my thoughts,
misskoji

 

[Cort]

Sorry you had to be the one; it sounds like it could be any number of things and that you'll won't be the only one with this result. At least we learned alot about PCR.

That does sound like a difficult situation - determining whether an in between signal is evidence of infection or not. Hopefully as they refine their techniques they'll get more easily defined results; either its there or its not.

Its obviously not a simple process.

 

[acer2000]

I think part of the issue here is that we all are so hopeful that this is a big piece of the puzzle if not "it" that we assume that all of the "Science" has been done and validated. Its just not so at this point. Not only do they have to replicate the study in other patient groups with the same symptoms, but they also have to validate the assay. Meaning that they need to prove that it shows the virus reliably in samples that they know have it and shows negative when they know it doesn't-and have other labs replicate the testing methodology independently. It sounds like they don't have it down 100% yet with the testing.

Also, as others have stated, PCR testing isn't foolproof. For example, I got sick after going to south america once and I was tested for Chagas disease which is a nasty parasite. They have to run 4 different PCR assays and cross reference them to figure out if you have it because no one (or two, three) by themselves are sensitive/specific enough to detect the parasite. And thats assuming the DNA is in the blood sample they took. So I think we have a ways to go with this test, which is why I think Coffin encouraged CFS patients to wait until there is a validated and approved test.

I'd even question a positive PCR result at this point, unless they can retest you and get the same result, or you test positive using all of the methods (antibody/culture/PCR). PCR can be false positive as well...