Objectives:

Haemodialysis patients are a risk group for HBV and HCV infections. Occult HBV infection is defined by detection of HBV-DNA in absence of HbsAg. Occult HCV infection is defined by presence of HCV-RNA in absence of anti-HCV. The aim of this study is to determine the prevalence of occult HBV and HCV infections and the diagnostic utility of anti-HCV and HBsAg as markers of HCV and HBV infections in haemodialysis patients since it has important implications in the dissemination of these diseases.

Methods:

We have studied prospectively 61 patients (33 males, 28 females, mean time in haemodialysis 41 months, range 1–256, mean age 65 years, range 28–83). Blood samples were drawn before dialysis treatment. HBsAg, anti-HBc, anti-HBsAg and anti-HCV were studied by an automated EIA (Asxym, Abbott Diagnostics). Detection of HBV-DNA and HCV-RNA was performed by an automated PCR system (Ampliprep and Amplicor, Roche Diagnostics). The limit of detection is 200 c/mL and 50 IU/mL, respectively.

Results:

HBsAg was detected in none of the patients (0%). Anti-HBc and anti-HBs were detected in seven patients (11.5%) and anti-HBc alone in two patients (3.3%). Anti-HBsAg was present in 35 patients (57.4%). HBV-DNA testing was performed on all the samples and none resulted positive. Anti-HCV was detected in seven patients (11%). HCV-RNA testing was performed on all the samples (anti-HCV positive and anti-HCV negative) with six being positive. These six positive HCV-RNA samples were also anti-HCV positive. None of the anti-HCV negative patients has HCV-RNA in serum.

Conclusion:

Prevalences of HBV-DNA in absence of HBsAg as variable as 19, 36 and even 58% have been reported in haemodialysis patients. The authors have studied the presence of HBV-DNA by in-house assays. Prevalence may vary depending on the assays used to detect HBV-DNA. Regarding HCV infection, some investigators have found prevalence rates of 9% of HCV-RNA positivity without anti-HCV in the serum of haemodialysis patients. Other authors have not confirmed these data. In our study, the prevalence of occult HBV and HCV infection is null. HBsAg and anti-HCV are very useful markers for identification of potentially infectious cases of HBV and HCV hepatitis in the haemodialysis setting.