Standardization of hepatitis C virus RNA quantification

Area of Science:

• Virology
• Hepatology
• Clinical Chemistry

Background:

• Hepatitis C virus (HCV) RNA quantification is recommended for tailoring antiviral therapy duration.
• Standardization of HCV RNA units is lacking, hindering clinical implementation.
• HCV genotypes 1, 4, and 5 treatment duration can be optimized using viral load monitoring.

Purpose of the Study:

• To establish clinically relevant hepatitis C virus RNA loads in standardized international units (IU).
• To enable routine clinical and research applications using validated quantitative assays.
• To define a decision threshold for adjusting interferon alfa/ribavirin therapy based on viral load.

Main Methods:

• Utilized two quantitative HCV RNA assays: Superquant and Cobas Amplicor HCV Monitor v2.0.
• Measured HCV RNA loads in IU/mL using the Cobas v2.0 assay.
• Correlated results between the two assays (r=.932, P<.0001) and converted units.

Main Results:

• The Cobas v2.0 assay demonstrated linear quantification and satisfactory accuracy/precision in IU/mL.
• A strong correlation was observed between the Superquant and Cobas v2.0 assays.
• A threshold of approximately 800,000 IU/mL (5.9 log(10) IU/mL) was identified, equivalent to 2,000,000 copies/mL (6.3 log(10) copies/mL) in Superquant.

Conclusions:

• All HCV RNA quantitative assays should report results in international units (IU) and be validated.
• The proposed threshold of 800,000 IU/mL is recommended for tailoring interferon alfa/ribavirin treatment duration.
• Standardized quantification facilitates personalized treatment strategies for hepatitis C virus infection.