Confusion about UND

[jankar]

What does UND really mean?

I had a result of UND<15 at week 4, someone else a UND<10 at week 4.  Is this result sensitive enough to base a decision on 24 weeks or 48 weeks?  Another suggested we needed weekly or daily tests in the first four weeks to make a decision, another suggested that those results are still detectable and if present at week 12 in the same levels, needs to result in 72 weeks treatment.

Thanks for all the research responses - I am particularly interested in results for 1b on Pegaysus 2a and Ribavirin as those results differ I think to the results from all Geno 1's and Pegysus 2b

[copyman]

i think you can safely rely on that test that goes down to 15. The chances of having a VL under that number would be really unusal. I would get the more sensitive "qualative" test 4 , 12 & 24 weeks after stopping tx, this will simply tell you if you have HCV or not, no VL. I agree with the other posters that you look like the perfect cadidate to tx only 24 weeks and spare your body an extra 24 weeks of these harsh drugs. Like I have posted before I believe the permanent damage from these drugs come in the 2nd half of tx. The longer you subject your body to them the better chance of permanent damage. Best of luck

[zazza]

I had a detectable but not quantifiable reading at week 12 with the Taqman <15 IU/ml. The laboratory doctor told me this meant I had somewhere between 5 and 20 IU/ml. This sounds to me that in reality even virus below the stated sensitivity can get detected. Anyway my doctors tell me that it does not matter if we use <15, <10 or <2. They are equally good. Anybody ever here of anyone having a viral load of 4 or 7 IU/ml, for example? They just don't come that low.

[jmjm530]

I may be reading it wrong -- and perhaps your Taqman test does indicate positives below the quantifiable limit of 15 IU/ml.

That said, in general a test will not detect below it's stated sensitivity. For example, if a test states it's sensitivity as 10 IU/ml, it will not pick up a viral load of 5 IU/ml. It won't quantify it and it won't even mention it. Heptimax, for example has a lower limit of 5 IU/ml. It will not quantify or qualify below that limit. As to tests picking up a "4" or a "7", this is possible with a test like LabCorp's Quantasure which goes down to 2 IU/ml. I don't think it will quantify that low but it will qualitate similar I imagine to what your doc said, except that the lower limit of the range is 2 instead of 5.

[jmjm530]

To clarify, I'm not  contradicting your doctor and have no reason to believe that is how your result should be interpreted for your particular test.  My point(s) are that most tests do not work like this in terms of lower limit sensitivity as I read your inference, although I may have read it wrong.  The way they work is that if the lower sensitivity of the test is "x" then any virons present below "x" will still give an UND result, i.e. nothing will be picked up below the detection limit whether that limit be in a quant or qual test.

-- Jim

[Deb_c430]

Sometimes when you a person is having a  quandry about something, you find the answer, Thanks!  

[zazza]

You are reading me correctly. And this doctor is a very knowlegeable hepatitis specialist. I am certain he knows what he talks about.

I have not read up on this myself, but I figure that it might be that they can not guarantee they will pick up viral loads below 15 IU/ml, so they set the limit there. I understand it to be that so low viral loads as 5 and 15 IU/ml do not differ so much in test appareance, so it actually becomes difficult to tell them apart. And I don't think it matters what test you use.