[The clinical significance of quantitation of HBV DNA in serum-comparison of the branched-DNA assay with the second-generation digene hybrid capture assay and long-term observation].

Background/aims: Serum levels of hepatitis B virus (HBV) DNA are direct measures of viral replication in hepatocytes. We compared branched-DNA assay (Quantiplex(TM), bDNA) and Hybridization Capture II (HCII), and evaluated the clinical significance of HBV DNA quantitation in the natural course of HBV infection.

Methods: We analyzed results of bDNA in 324 serum samples from 83 untreated male patients with chronic hepatitis B. Mean follow up period was 11.8 years. HCII was also performed in 157 arbitrarily selected samples.

Results: HBV DNA levels measured with two assays were very similar (r(2)=0.893, p<0.0001). HBV DNA detection rate of HCII was 6.4% higher than that of bDNA in HBeAg positive samples. HBV DNA detection rate was higher in cases with higher ALT. Among 73 patients with initial diagnosis of chronic hepatitis, 38 patients (52.1%) experienced progression to cirrhosis, and hepatocellular carcinoma (HCC) was developed in 9 (12.3%). HCC was developed in 5 (50.0%) of 10 patients with initial diagnosis of cirrhosis. While HBeAg positive rates during chronic hepatitis, cirrhosis and HCC were 57.8%, 55.0% and 14.3%, respectively (p=0.006), HBV DNA detection rates were 70.6%, 64.0% and 42.9%, respectively (p=0.08). Especially in HCC, the discrepancy between HBeAg positive rate and HBV DNA detection rate may suggest the appearance of variants which cannot produce HBeAg.

Conclusion: Both HCII and bDNA were similar HBV DNA quantitation assays for clinical use. HBV DNA level correlated with the severity of liver disease. Screening tests for HCC should be recommended in patients whose HBeAg is negative and have detectable HBV DNA.