HR, Jim, mremeet, Goofy Dad, anyone that has knowledge of pcr testing?

[prettydamscared]

Hi everyone,

Some of you have been following the saga of my "29" at week 12 as well as APK's.  I do think/hope my 29 at week 12 is an "artifact" or false positive but for my own peace of mine, I want to comfirm that by getting the most sensitive and accurate pcr test available.  Asked my doctor about it yesterday and the study can't provide one more sensitive than the one we've all been discussing but he told me I was welcome to get one on my own.

There's a lot of confusion in my mind surrounding these tests.  Searched the archives and found something Goofy Dad posted in Nov.06

http://www.natap.org/2005/HCV/122805_04.htm

Conclusions: Among patients treated with combination therapy for chronic hepatitis C, the TMA test detects HCV RNA in all specimens that are Amplicor-positive, as well as an additional 21.6% that are Amplicor-negative. The increased sensitivity of the TMA test can be helpful in identifying patients with low levels of HCV RNA who are likely to relapse when therapy is stopped. Furthermore, among patients with EVR and a negative Amplicor test at W20, persistent detection of HCV with the TMA test during therapy predicts failure to achieve SVR.

*FDA-approved for detection of HCV RNA as evidence of active infection.

Can someone explain to me like I'm five years old what the above means. Also, HR posted on 11/12/06 the following:

(Continued below)

[Kalio1]

Im not sure how important the sensitivity of the test being matters be it down to 2, or 10 or 50. If you relapse, the most common way is to have the virus come back quickly and in plenty of numbers to be detectable by any of those tests. If it's back, it's back and that will be obvious. Some do relapse after the first few weeks or months and some just have a ssmidge of virus show up at first when they relapse but the majority would be detectible by most measures is what I was told.
I'd  time my EOT PCR test at 2 weeks past last shot and then at least another test at 12 weeks and again at 24 weeks. If you can get the doc to do it, I't try to get them weekly like Jm suggests if you plan on continuing therapy.

[prettydamscared]

HR's post to MissMiss:

"9 month after SVr you need to use Labcorps NGI Ultraqual LC#140609. Nothing else and as sensitive as Heptimax. I have discussed prev. why NGis contamination issues are dramatically less than other labs and the whole facility is FDA certified. Since every contamination could destroy 512 plasmadonations and yet 1 slightly positive diluted in a pool of 511 negs MUST BE DETECTED, you can imagine the extremes which had to be established there."

I'm assuming there's no particular reason for HR to have suggested this test to use 9 months after svr other than the fact that MissMiss was going for her 9 month pcr.  Should I use the one suggested above by HR or is this a QUALITATIVE test?  Have to admit, I'm confused easily these days and don't have the energy to thoroughly research this.  I'm not even sure how important it is, i.e., is one drastically different from another.  I'm just confused over the 29 issue and no amount of explanation from my doctor fully allayed my concerns so just want to be sure I'm undedected at this point. (22 WEEKS) I would prefer to use LabCorp if possible because that's who my GP deals with and it would be easier.

Thanks in advance for any help.

Char

[mremeet]

Oh, one other thing I'm curious about re the often touted TMA - are low level qualitative tests more reliable than low level PCR quantitative tests? If low level qualitative tests have a higher margin of reliability/confidence, that might also be a reason why it's referenced so much as the apparent gold standard of HCV +/- referees.

Also char here's a couple of Labcorp sites you might find interesting:

Here's the test I used: (quant down to 2 IU/Ml)

http://www.labcorp.com/datasets/labcorp/html/chapter/mono/id004600.htm

And here's an ultraqual: (qual down to 2 IU/ml)

http://www.labcorp.com/datasets/labcorp/html/chapter/mono/id003400.htm

[jmjm530]

PDS,

Let me make it simple first. If you want to privately get a readily available and sensitive test, either of the following will do just fine. Both have a sensitivity of 5 IU/ml.  My preference would be #2, mainly because that particular test is run exclusively at Quest's Nichols Institute at Cupertino, California, regardless of where the blood is drawn.

(1) Quest Diagnostic's "Heptimax".  

(2) Quest Diagnostic's "HCV RNA Qualitative TMA".

-----------------------
Less simple -- the test you've already taken should do equally as well if they will administer it right away, which is what you probably (and should) want. From what I understand, your "29" means you were detectible somewhere between 10 IU/ml and 30 IU/ml. But if it were me, at this point, why not go to another lab just for peace of mind (and clarity). Therefore one of the two tests I mentioned will do the trick.

-------------------------------

FlGuy,

If the intent is to catch relapse "as soon as possible", then you would want to test EOT and weekly thereafter, at least until week 4 or 6 -- as most relapses appear to occur within the first month after stopping the treatment drugs. If it's a case of judiciously spending your money, then I'd say test at weeks 2 and 4 as a compromise but I have nothing scientific to back it up. In any event, you would want the most sensitive test possible, such as one of the two tests I mentioned above to PDS. Some also test a couple of weeks before EOT, so in case of a positive they can continue on with the drugs if that is part of their strategy. In my case, I tested at weeks 2 and 6 -- the week 2 test was because I was getting antsy and week 6 because a negative 4 week post tx test is heavily associated with SVR, even more so I assumed at week 6. I had no plans to jump back into treatment however, regardless of results, so my concerns were different than yours.

All the best,

-- Jim

[Hepatitis Researcher]

When you strongly suspect to be negative by an ultrasensitive test then  you run a qual test like HCV NGIs Ultralqual ( Labcorp#140609) This will show you negative if you are below 2 international units.

If you think you are very low but not ultralow, then you order HCV NGI Quantasure ( LC#140639) that will give you a number from 2 iu to 2000000 iu. or not detectable below 2 iu.

Its a combo quant qual test. Max sensitivity combined with quantitation.

Why not always use the second one? Its more work and therefore more expensive.

[Imagine]

I guess my question would be is how many does it take to tango/replicate? The international unit is still a little confusing to me. If two people of the same genotype, same age, same stage, both are undetected at wk4 using the same pcr testing methods and remain so through 48wks, why then would one achieve SVR and the other relapse?

I am not sure if there is an answer but sure would welcome possibilities. It is something I really wonder about since I have relapsed. I know the why will not help me but it sure would satisfy my curiosity. Could it be the particular strain of say 1a that these two people had that makes the difference?