Abbott RealTime PCR quantification after successful therapy

[hippomanic]

I've done the Abbott RealTime PCR quantification instead of Amplicor ® HCV v2.0 qualitative test. I count 7 years after successful therapy PEG-IFN/ribavirin (SVR). Now I wonder how reliable quantification PCR instead of qualitative PCR to identify my status SVR. Is there a big difference between these two tests to determine the SVR?
Sorry because of bad writing :))))

[willbb]

It matters not at this juncture whether or not you have had viral load checked by a Quant or  a Qual, given viral load upon relapse would be significantly higher that either tests "Lower limit of Detection." (LLOD)

Congrats on your long term SVR..

Will

[flcyclist]

First, major congrats for your successful treatment.  I'm curious, why test after 7 years?  Is this done annually just to make sure?

I agree with your statement that the Quantitative PCR in this case is more sensitive than the Qualitative test.  I believe it was the reverse prior to the recent improvements in the quantitative assays.

Qualitative  -  Amplicor® HCV v2.0   50 IU/ml  (Lower Limit of Detection)

Quantitative - Abbott RealTime          30 IU/ml  (Lower Limit of Detection)

I don't understand why someone would chose to run the qualitative assay now since the quantitative assays have improved their sensitivities so much.   Unless these numbers are wrong, maybe I'm missing something??

For more information:
Qualitative detection assays are based on the principle of target amplification using either “classic” polymerase chain reaction (PCR), “real-time” PCR or TMA [ 5 ]. HCV RNA is extracted and reverse transcribed into a double stranded complementary DNA (cDNA), which is subsequently processed into a cyclic enzymatic reaction leading to the generation of a large number of detectable copies. Double-stranded DNA copies of HCV genome are synthesized in PCR-based assays, whereas single-stranded RNA copies are generated in TMA. Detection of amplified products is achieved by hybridizing the produced amplicons onto specific probes after the reaction in “classic” PCR or TMA techniques [ 5 ]. In “real-time” PCR, each round of amplification leads to the emission of a fluorescent signal and the number of signals per cycle is proportional to the amount of HCV RNA in the starting sample [ 5-7 ]. Qualitative detection assays must detect 50 HCV RNA IU/ml or less, and have equal sensitivity for the detection of all HCV genotypes. The lower limit of detection of the qualitative, non quantitative reverse-transcriptase PCR-based assay Amplicor® HCV v2.0, or of its semi-automated version Cobas® Amplicor® HCV v2.0 (Roche Molecular Systems, Pleasanton, California) is 50 IU/ml, whereas that of the TMA-based assay Versant® HCV RNA Qualitative Assay (Bayer HealthCare) is 10 IU/ml (Table 1). Real-time PCR assays, which are also able to quantify HCV RNA, have lower limits of detection of the order of 5-30 IU/ml when they are used as purely qualitative, non-quantitative assays.

http://www.medsci.org/v03p0035.htm

[hippomanic]

I got the result, "HCV RNA was not detected" I do not understand why the Qualitative PCR is more sensitive   than Quantitative PCR. Abbott RealTime sensitivity 30 IU / mL and Amplicor ® HCV v2.0 detects HCV RNA levels as low as 50 IU / mL?

[frijole]

Yes, I agree with tazz,  The qualitative is the most sensitive.  If you are undetectable with that you are good to go.  Congrats on 7 years of SVR.

[tazz1985]

Qualitative PCR is more Sensitive than Quantitative PCR...and Generally after attaining SVR.. Gastroenterologist usually order for a Qualitative PCR. But it doesn't matter because if you have successfully cleared the HCV virus then both forms of PCR (Qual and Quant) will be NEGATIVE... be optimistic, best of luck and stay happy...  :))