Help. I think I'm giving wrong advice.

[carol411]

I have a friend who is working in a temporary job for the VA.  They gave her a physical and hep c antibodies showed up.  She called me in a panic and I told her it was way too soon to worry.  Then the RIBA test showed positive and I told her it was still too soon to worry, she could have cleared on her own.  So she called with the PCR results and said it said less than 43.  Yay, I told her, that's what I'm hoping to see after all this nasty tx.  Well, last night she called again.  She had received a letter from her county health department on how to deal with hep c.  Of coarse she was panicked yet again.  In Oregon, it is law that all hep c cases are reported to the county health departments and they contact the patient.  Anyway, in the conversation, she said that her PCR said less than 43, detected.  She'd never said detected before and has ignored my requests to email me the tests (she lives 350 miles away and does not enjoy computers).  Now I'm wondering if telling her over and over not to worry was a mistake.  She had blood transfusions in the early eighties and like many of us had her wild party days so I was stuck in the thought that if she had been infected it was years ago and she had been one of the lucky ones that cleared on her own.  Now because of the less than 43, detected, I'm wondering if this could be a new infection.  

The tests were all in preparation of hiring her full time with benefits.  Now, the funding has disappeared.  Somehow that sounds awfully convenient, but funding is tight everywhere so maybe it's a sad coincidence.  I told her to get another PCR.  Any thoughts?

Thank you,
Carol

[Bill1954]

Hi Carol,

When a PCR quantitative results state <43 IU/mL (detected) it generally occurs when someone is undergoing antiviral therapy. My understanding is that while some of these tests are capable of detecting very low levels of viremia, they’re only allowed to report quantitative results to a certain numerical value.

I think you’re right; another viral assay is in order. If she’s somehow offered options, I think perhaps her best bet would be a sensitive ‘qualitative’ PCR test; she only needs a yes/no (pos/neg) result at this point.

I guess she could have somehow acquired the infection recently, but even then I think intermittent viremia isn’t all that common; we’d think she’d have a significant load even under these circumstances.

Serial PCR testing should clear this up; I bet she’s on pins and needles right now, huh?

Good luck,

Bill

[Fnzol]

"My understanding is that while some of these tests are capable of detecting very low levels of viremia, they’re only allowed to report quantitative results to a certain numerical value."

The limit of detection for the test is 43 units; that's as low as it can currently go.  That's why the test is resulted as <43.  It might be zero, it might be 42.  

[Bill1954]

Yes; but my limited understanding is that they have the capacity to detect presence of viremia lower than they are permitted to express in quantitative manner; thus the result ‘<43, detectable’, no?

In any event, I imagine another PCR test will be ordered…

-Bill

[Fnzol]

No.  Not until approved to do so.  These are medical devices approved by FDA.  The package inserts specify current detection limits and are part of the labeling of the devices.  Labeling is approved and the device cannot be marketed legally without that approval.  

The kit manufacturer must demonstrate and validate efficacy and must submit an amended application if they wish to change the detection limit (the labeling).  

[carol411]

Bill,
Yes, she's on pins and needles and imagining all kinds of symptoms that I have never heard or read about :)  I called and read her your response to the question and she's decided to have another PCR even though she will have to pay for it.  I'll keep my fingers crossed for her, but I think she's fine.  If she has hep c it sure seems the viral load would be way above 43.  Thank you for the quick response!

Fnzol,
I don't know what device you're referring to.  There is a quantitative or a qualitative PCR test.  One says how much virus the other says virus/no virus.  It seems they ran the wrong test so for peace of mind she will have to do the other.  I think the outcome is likely to be zero.  Thank you!

Carol

[copyman]

Sounds like she did the labcorp standard pcr test which measures down to <43. I'm very familiar with that test and if undetected it will read exactly:
" Hepatitis C Quantitation  <43,  HCV RNA NOT detected"  "
"HCV log10 Unable to calculate result since non-numeric result obtained for component test"

If she wants to make sure and put this behind her tell her to get this test from labcorp, "NGI HCV Ultraqual" This is the most sensitive test available. If she is negative with this test then she can take it to the bank that she is really negative!
It is also much cheaper then a PCR since she is paying for it herself.
Wish her best of luck from me.

[Fnzol]

"I don't know what device you're referring to."
__________________________________________

In-vitro diagnostic test kits, which these PCR tests are, are medical devices under the law.  "Device" is a term broader than what you're thinking.  

A "device", as defined in the Food, Drug, and Cosmetic Act, as amended (one of the Federal statues that gives FDA its authority), is, to paraphrase, ...an article, contrivance, in-vitro reagent...the intended purpose of which is to diagnose disease in man or animals...and/or cure...mitigate disease...and which does its thing chemically on or in the body but is not metabolized.  

The definition is very similar to that of "drug", except that drugs are intended to be metabolized.  

Both definitions include the very important proviso "intended use".  This is part and parcel of what makes a drug or device a drug or device.  What the manufacturer claims it will do, as indicated on stickers or tags on the article, in its package insert, in its advertising.  Approval of a drug or device includes approval of its insert--its instructions for use--and this must tell the end user how to interpret the results, in the current case, for example, of discussing test kits.  

The best that the kit can do currently is to count 43 copies.  If it comes up less than that, they must report "less than 43".  That's the limitation as bounded by the approved labeling of the device.