One-Step Reverse Transcriptase qPCR Method for Serum Hepatitis B Virus RNA Quantification

In recent years, serum hepatitis B virus (HBV) RNA has been identified as a promising noninvasive surrogate biomarker of intrahepatic covalently closed circular DNA (cccDNA), detection of which requires an invasive liver biopsy in patients with chronic HBV infection. It is impractical to detect intrahepatic cccDNA as a routine diagnosis for chronic hepatitis B (CHB) patients in clinical management. Here, we describe a detailed protocol for serum HBV RNA quantification, which can reflect the activity of intrahepatic cccDNA. The procedure includes three major steps: (1) Simultaneous isolation of HBV DNA and RNA from patients’ serum, (2) DNase I digestion for removing HBV DNA contamination, and (3) HBV RNA quantification by one-step reverse transcription qPCR.