Evaluation of blood samples collected by dried blood spots (DBS) method for hepatitis B virus DNA quantitation and its stability under real life conditions

Abstract

We evaluated the diagnostic performance of dried blood spots (DBS) compared to plasma for detection and quantification of HBV-DNA under real-life conditions. Blood specimens from 100 known cases of chronic hepatitis B (CHB) requested for quantitative HBV-DNA were included. In a subset of 20 patients, three sets of DBS cards were prepared, one kept at -80°C, the other two kept at room temperature for 7 and 14 days, respectively. DBS method demonstrated sensitivity, specificity, and positive predictive value of 95.3%, 100%, and 100%, respectively in comparison to plasma. The mean HBV-DNA load in plasma was 4.8 log10 IU/ml while in DBS was 4.3 log10 IU/ml with a strong correlation (R2=0.9087). No significant change in viral load was observed at room temperature for up to 14 days. This study suggests that DBS for HBV viral-load quantitation is a good alternative to plasma as it is stable during storage at room temperature and therefore allows easy handling, storage, and transport of specimens in resource-limited settings.

Keywords

• Diagnostic accuracy
• Dried blood spots (DBS)
• HBV DNA
• Virological testing
• Hepatitis