Viral Load Testing: The difference 5 IU / mil Makes

[coloradogirl]

I go in for my 4th week blood tests tomorrow, so to make sure things go smoothly, I checked to see if it made a difference in what test is used, and what lab can perform the test I require.

My doctor ordered a Nucleic Acid Direct Probe (87520), an HCV-RNA by RT-PCR, reflex to TMA, which is sensitive down to 10 (with some sources indicating 5-10 in sensitivity).

The Kaiser Permente lab initially used a Cobas AmpliPrep/Cobas TaqMan HCV assay, which is sensitive down to 15. Quest uses the TMA test ordered. So I wondered what the need for the TMA test is all about.

I finally found something difinative on the Quest Lab web site that clarified the procedure they use. They test the sample using the TaqMan assay, and if it comes out below 15 then they perform the TMA test for the finest results of quantifiable virus load. They send the blood work to their lab in Chantilly, VA where specialists conduct the TMA test.

The TMA test is costly and not paid for by insurance, but the results could make the difference for me to opt for addition of Ribivarin for the last 8 weeks. From what I have read, it can also determine whether to prolong treatment for some patients,  or cut a 24 week treatment to a lesser duration.

I am curious what tests have been ordered for you all. Are there any like what have been ordered for me?

[DisabledHepcat]

Stop with all the small technical data of 5 iu versus 15 iu.
It's either less than 15 iu or 500,000 iu and above.
The difference between 5 iu and 15 iu is non concerning.
Be happy !  it's not 500,000 iu and above.

[Lynn K]

The only tests that matter really are the 12 week post and the 24 week post. In general the treatment is per the prescribing information.

I am not aware of any recommendations from the AASLD for changing the recommended treatment based on viral load. The only group that maybe it might be important to is the 8 week vs 12 week group.

Do you have a reference to changing tx length based on viral load testing?

If you don't have cirrhosis as a GT 1a with prior tx you should receive 12 weeks. If you do have cirrhosis like I do you should treat for 24 weeks. I was not detected at 4 weeks and 12 weeks and I have no desire to end treatment early on that basis.

I was not detected last year on Sov/Oly at 4 weeks and 12 weeks EOT but relapsed when tested 12 weeks later back up to 2.4 million IU/mL a long way from not detected.

These testing sensitivity differences are splitting hairs and have no relevance to the thing we are trying to acheive here being cured of hep c which will only be able to be determined by testing for the return of the virus back to levels prior to treatment.

Testing while on treatment will not change what happens after EOT.     

Good luck on treatment

[coloradogirl]

I am only trying to figure out why my doctor would ask for this test. His background is in research at the University of Colorado, Denver under Dr. Greg Everson, so he has quite a bit of experience with HCV.  It could be he has seen a lot of test results that fluctuate such that he feels it is warranted.  At Quest, the test is only conducted of the viral load of the PCR test is under 15.

One caveat in my case is that they couldn't produce results from my FibroSure test, since one of the parameters was way out of bounds. So I don't know for sure what stage I am.

The information I dug up on the use of the TMD test is at the link below. It doesn't mention Harvoni specifically, but was published in 2014, and was used in current treatment offerings.

http://www.biomedcentral.com/1471-2334/14/S5/S8

[Lynn K]

I am guessing he may be wanting to use your information in his research as you said he is a research scientist. Possibly he wants to collect more data on you than might be done in another situation with another doctor and patient all other factors being equal.

I know some here were tested for the Q80K polymorphism and also the IL28B I have been tested for neither one. I do think that I probably have all the negative predictors for response based on my history.

Thanks for the link good information in there related to some other discussions about being low level but detected and SVR.

It appears they are comparing the new DDA's we are taking to the old boceprevir telaprevir to be useful in treatment duration I guess they are considering if that is something to be considered with Harvoni as all are searching for ways to maximize efficacy without sacrificing effectiveness of treatment.

I guess that is what research scientists tend to do is split hairs lol but for most these small details really don't matter.

Since you seem like you maybe a bit younger that me and haven't had hep c as long odds are you probably don't have much liver damage. The fibrosure test does have limitations as do all tests. 

Sounds like you have a great doctor so that is great!