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24 week UND!!! Are PCR's unreliable?
Good Morning Vietnam!
I got 21 week PCR yesterday and called the dr. I read to me UND, but wasn't sure b/c of the language. Of course I am happy of this result, but it is so hard to understand.
The comments in parens are the 12 week PCR;
Hep C RNA >1.9 (8) (this said Not Qnt last time)/
<1.9 log IU (same as before)
*(8) Viral load is Result for HCV RNA is LESS Than 75 IU/ML
...Results below the limit of detection (1.9log IU/mL) will be reported as >1.9 log IU/mL. Results between 1.9 and 2.3 log IU/mL (75 to 200 IU/mL) will be reported as "HCV RNA detected below the limit of quantitation."
Would you say this means I am UND? Why the Not Qnt last time? Ultrasound says fatty liver versus cirrhosis, this is scary as he said it could be one or the other.
The GI told me that PCR's are SO unreliable that he doesn't put too much stake in them. Interesting! He says he was one of the first Dr's in the world to do PCR's and has done them by hand. Claims that the same blood sample can change from hour to hour as far as VL. If this is the case why do we put our lives in the reports of PCR's. I asked about getting a more sensitive test or TMA etc. He said they are all the same. He will do a Qualitative next time...I really thought this was something to discuss here. If PCR's are so unreliable and fluxuate, then why do we say someone that has a breakthough with a few copies stop tx?
I got 21 week PCR yesterday and called the dr. I read to me UND, but wasn't sure b/c of the language. Of course I am happy of this result, but it is so hard to understand.
The comments in parens are the 12 week PCR;
Hep C RNA >1.9 (8) (this said Not Qnt last time)/
<1.9 log IU (same as before)
*(8) Viral load is Result for HCV RNA is LESS Than 75 IU/ML
...Results below the limit of detection (1.9log IU/mL) will be reported as >1.9 log IU/mL. Results between 1.9 and 2.3 log IU/mL (75 to 200 IU/mL) will be reported as "HCV RNA detected below the limit of quantitation."
Would you say this means I am UND? Why the Not Qnt last time? Ultrasound says fatty liver versus cirrhosis, this is scary as he said it could be one or the other.
The GI told me that PCR's are SO unreliable that he doesn't put too much stake in them. Interesting! He says he was one of the first Dr's in the world to do PCR's and has done them by hand. Claims that the same blood sample can change from hour to hour as far as VL. If this is the case why do we put our lives in the reports of PCR's. I asked about getting a more sensitive test or TMA etc. He said they are all the same. He will do a Qualitative next time...I really thought this was something to discuss here. If PCR's are so unreliable and fluxuate, then why do we say someone that has a breakthough with a few copies stop tx?
I've go to wonder about your doctor's expertise when I read:
"I asked about getting a more sensitive test, he said it wouldn't make a difference."
This is just wrong. I'd watch that guy closely if he was treating me.
Mike
"I asked about getting a more sensitive test, he said it wouldn't make a difference."
This is just wrong. I'd watch that guy closely if he was treating me.
Mike
As the first excerpt form http://www.clevelandclinicmeded.com/hcv/lab.htm
shows PCR is simply one method of testing for the presence of the virus itself, not somply the presence of the antibodies.
It also goes on in the second excerpt to suggest that the quantitatice test is more sensitive than the qualitative test.
Other studies I've read suggest that the TMA is more sensitive than the PCR, and if I recall correctly significantly so.
1) "The HCV RNA test determines the presence of the virus itself rather than its antibodies. The HCV RNA test measures the amount of HCV RNA in the blood via target amplification with reverse transcriptase polymerase chain reaction (PCR), transcription-mediated amplification (TMA), or a signal amplification technique such as a branched DNA (b-DNA) assay. Amplification is necessary because the amount of virus in serum is generally very low. Regardless of the method of amplification, HCV RNA detection represents definitive proof that an infection exists.16
The sensitivity of the different types of amplification varies. The TMA is the newest of the HCV RNA assays, and it is also the most sensitive.It may have the potential to detect relapsed HCV infection earlier than PCR.16 Although qualitative HCV RNA assays are more sensitive, they do not provide a quantitative value for the viral load.
HCV RNA is customarily done at 12 and 24 weeks during the treatment course, at the end of treatment, and 6 months after treatment has been completed.11,16 In the past, comparison of viral levels between assays was impossible. Adoption of standardized units of measurement (IU/mL) has eliminated this problem.16,17,19 It should be borne in mind that differences in HCV viral load of 0.5 log or less are within the range of testing variability and may not have clinical significance."
2) "EIA is the most widely used initial test for HCV infection because of both its accuracy and its low cost.
A positive EIA is usually followed by an HCV RNA test to document active infection. Since HCV RNA levels in patients with chronic HCV infection are within the range of the quantitative assays, many experts evaluate EIA-positive patients with a quantitative HCV RNA assay. In unusual cases, the HCV RNA quantitative test may be negative, but the (more sensitive) HCV RNA qualitative assay will be positive."
shows PCR is simply one method of testing for the presence of the virus itself, not somply the presence of the antibodies.
It also goes on in the second excerpt to suggest that the quantitatice test is more sensitive than the qualitative test.
Other studies I've read suggest that the TMA is more sensitive than the PCR, and if I recall correctly significantly so.
1) "The HCV RNA test determines the presence of the virus itself rather than its antibodies. The HCV RNA test measures the amount of HCV RNA in the blood via target amplification with reverse transcriptase polymerase chain reaction (PCR), transcription-mediated amplification (TMA), or a signal amplification technique such as a branched DNA (b-DNA) assay. Amplification is necessary because the amount of virus in serum is generally very low. Regardless of the method of amplification, HCV RNA detection represents definitive proof that an infection exists.16
The sensitivity of the different types of amplification varies. The TMA is the newest of the HCV RNA assays, and it is also the most sensitive.It may have the potential to detect relapsed HCV infection earlier than PCR.16 Although qualitative HCV RNA assays are more sensitive, they do not provide a quantitative value for the viral load.
HCV RNA is customarily done at 12 and 24 weeks during the treatment course, at the end of treatment, and 6 months after treatment has been completed.11,16 In the past, comparison of viral levels between assays was impossible. Adoption of standardized units of measurement (IU/mL) has eliminated this problem.16,17,19 It should be borne in mind that differences in HCV viral load of 0.5 log or less are within the range of testing variability and may not have clinical significance."
2) "EIA is the most widely used initial test for HCV infection because of both its accuracy and its low cost.
A positive EIA is usually followed by an HCV RNA test to document active infection. Since HCV RNA levels in patients with chronic HCV infection are within the range of the quantitative assays, many experts evaluate EIA-positive patients with a quantitative HCV RNA assay. In unusual cases, the HCV RNA quantitative test may be negative, but the (more sensitive) HCV RNA qualitative assay will be positive."
I wonder if they had tested your blood an hour later it would have said UND. That makes me wonder if some people are thinking they are UND at 12 weeks, not txing for 72 weeks as you are, because they think that they were UND at 12 weeks. Perhaps if they did several PCR's over a day they would be more accurate. I hate to think that people are getting false info and basing tx options on this. It is good (not really!) that you found out and are extending. Maybe others are basing their tx time based on false readings. A concern.
I asked about getting a more sensitive test, he said it wouldn't make a difference. Obviously, it did for you and would have for me, if I knew I had a small amt. of VL.
I didn't realize that the same blood sample can change so much in a PCR in an hour. Really makes me wonder! If my PCR at week 12 was detectable, I would have been taken off tx right then and there by the ins. co. Such important decisions are based on these tests.
I asked about getting a more sensitive test, he said it wouldn't make a difference. Obviously, it did for you and would have for me, if I knew I had a small amt. of VL.
I didn't realize that the same blood sample can change so much in a PCR in an hour. Really makes me wonder! If my PCR at week 12 was detectable, I would have been taken off tx right then and there by the ins. co. Such important decisions are based on these tests.
I THINK what he means is that if you think of it this way...say you are UND to 75. All that means is that they can't count any LESS than that. So you COULD have 70 PER MIL left in your blood. Now if you times the amount of MLs of blood in your body...potentially you could have what trillions of virus's floating about BUT still be considered UND.
We all have to remember that.
When I tested at 4 weeks at 411...by the OLD testing down to 615 copies i WOULD have been told I was UND - but as you can see I was not at all.
Even with being tested down to 5...and coming up UND..that means if I had 2 per ml well - I don't know how many MLs of blood we have but there would certainly be enough to replicate and cause a relapse.
This is why I decided to treat for 72 weeks - hopefully it will knock the hiding ones out for Good.
Did that make sense? That was my take on why a doctor would say they are unreliable. But again...my guess you know?
We all have to remember that.
When I tested at 4 weeks at 411...by the OLD testing down to 615 copies i WOULD have been told I was UND - but as you can see I was not at all.
Even with being tested down to 5...and coming up UND..that means if I had 2 per ml well - I don't know how many MLs of blood we have but there would certainly be enough to replicate and cause a relapse.
This is why I decided to treat for 72 weeks - hopefully it will knock the hiding ones out for Good.
Did that make sense? That was my take on why a doctor would say they are unreliable. But again...my guess you know?
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