Lab Corp no longer offering <10 PCR.

[orleans]

Scared the c**p outa me for sure. As most of you know I dropped the RIBA a few weeks ago. Well I did a PCR, checking on break thru. When I called my lab lady she read the results saying "<43" HCV RNA not detected." I'm LIKE, what's this <43?? She doesn't know, she said it was the same test we've been doing from the start which is the 10 to 100,000,000 . (been UND <10 from week 2) Of course I'm thinking of the confusion during the Telaprivir trials and others. Well I'm a LITTLE worried at this point so she starts making calls trying to find something out. That was yesterday, got the word this morn. Lab Crop has stopped the 10-100,000,000 and in it's place is using a 43-69,000,000. The L.Corp lady told my lady that they considered this test more reliable and consistant. I am still UND. jerry

[jmjm530]

Can't speak to the relative accuracy of the different tests, but I thought the article posted earlier made a persuasive argument for standardization, i.e. reporting in IU/ml.

[apache1]

Yup, your right CS, that makes it 5, for sure.
Just wondering how sure they are, of their '5' number. Or for that matter, any of the other tests conversion factors.

I will fall back to my original thought (1mm = .004" anywhere in the world)  why is it necessary to use a iU/ml at all.
Seems to me, it cant get any more accurate or less confusing to call like it is,..
1virion = 1copy... 1 is one.


=============================================================
jim
As a researcher I can understand why you might prefer "copies" to IU/ml in the type of test you just mentioned. But if I read you correctly, you're speaking to a specific testing protocol. However, the problem as I see it -- and I believe as stated in the paper --  is that there are so many different tests out there that some sort of standardization was necessary so patients and their doctors worldwide could share meaningful information and observe universal guidelines.
=============================================================
Jim, maybe I am misunderstanding you.
To me it does not matter how many test there are. iU/ml de-standardizes the results. How is it standardized when one test uses 1ui/ml to equal 5.2 virons=iU/ml,  and another uses 1iU/ml to = 3.7 or 2.5, etc, as in your above chart of different tests protocols.
Isn't 1 virion equal to 1 virion standardization at its simplest ?

Got to be some tests inability to sometimes not be able to differentiate between 1 virion and globs of virions so the iU/ml gives them wiggle room for a miscount... maybe, just a thought.
Seems to me all tests are not created equally. So some tests do not want to stand behind their test enough to tell it like it is, 1=1.
Volla... here comes the ambiguous iU/ml to confuse the matter, and skew the comparison between tests... very convenient from some lesser tests.
IMO, smells of bean counters trying to justify the cost of there less accurate test to administrators.

[CockSparrow]

The TMA assay has been validated to have a sensitivity of 5–10 IU/ml or 25–50 copies/ml

Actually that makes it 5 doesnt it

HR
Sorry you lost the Post, i would have been really interested in reading it.
The different way of counting a single viron has driven me nuts fior ages.

CS

[CockSparrow]

Apache1 - Are you sure of the 5.2 factor for TMA
Yeah.
from Journal of Hepatology
Hepatitis C minimal residual viremia (MRV) detected by TMA at the end of Peg-IFN plus ribavirin
The TMA assay has been validated to have a sensitivity of 5–10 IU/ml or 25–50 copies/ml


http://www.specialtylabs.com/education/download_PDF/TN_1193.pdf

Hepatitis C Virus RNA DetectR™ [TMA]: Detects presence of Hepatitis C Virus RNA down to 10 IU/mL, to diagnose Hepatitis C Virus infection.
(Note: 5.2 copies/mL = 1 IU/mL; Bayer Corporation 2001)

CS

[jmjm530]

Very frustrating, that's happened to me more than once.

As a researcher I can understand why you might prefer "copies" to IU/ml in the type of test you just mentioned. But if I read you correctly, you're speaking to a specific testing protocol. However, the problem as I see it -- and I believe as stated in the paper --  is that there are so many different tests out there that some sort of standardization was necessary so patients and their doctors worldwide could share meaningful information and observe universal guidelines.

-- Jim

[Hepatitis Researcher]

Well I just wrote a 3 page explanation, why "robust single copy PCR" using electrophoresis and Southern blotting after the amplification  combined with limiting dilution techniques does allow to quantify a standard in absolute terms of "copies". Sadly this very detailed account was lost when submitting it. Thus I have to point to an earlier fairly detailed explanation of this aspect  that I posted quite a while ago.