The quantification of Hepatitis C virus RNA is essential for the everyday management of chronic Hepatitis C therapy.
Real-time polymerase chain reaction techniques are potentially more sensitive than classical polymerase chain reaction techniques, are not prone to carryover contamination.
Real-time polymerase chain reaction techniques also have a consistently wider dynamic range of quantification.
Thus, they are rapidly replacing other technologies for the routine quantification of Hepatitis C virus RNA.
Dr Jean-Michel Pawlotsky and colleagues from France extensively evaluated the intrinsic characteristics and clinical performance of Cobas Ampliprep/Cobas TaqMan.
It is the most widely used real-time polymerase chain reaction assay for Hepatitis C RNA quantification.
The researchers show that Cobas Ampliprep/Cobas TaqMan is sensitive, specific, precise, and reproducible.
|The overestimation increases with the viral load |
It has a broad dynamic range of quantification well suited to Hepatitis C virus RNA monitoring in clinical practice.
However, the team identified 2 technical issues that will have an impact in clinical practice.
First, the researchers noted that Cobas Ampliprep/Cobas TaqMan assay overestimates Hepatitis C virus RNA levels in undiluted patient samples.
The assay overestimates the Hepatitis C virus by approximately 0.6 log10 international units per milliliter on average.
The team observed that this overestimation increases with the viral load.
Second, the researchers found that the Cobas Ampliprep/Cobas TaqMan assay underestimates Hepatitis C virus RNA levels in about 15% of genotype 2 samples.
It also overestimates the virus in 30% of genotype 4 samples, probably because of mismatches with the target sequences due to the primer and/or probe design.
Dr Pawlotsky's team comments, "The Cobas Ampliprep/Cobas TaqMan platform is widely available, easy to use, and suited to high-throughput screening for viral genomes."
"The manufacturer should improve the Hepatitis C virus RNA kit to resolve these 2 important technical issues that may affect everyday management of Hepatitis C therapy."