Dried blood spots perform well in the quantification of HBV DNA and detection of HBeAg

Background Hepatitis B virus (HBV) DNA quantification and hepatitis B e-antigen (HBeAg) detection are recommended in the management of chronic HBV infection. The use of dried blood spots (DBS) collected with fingerstick could improve access to these tests in resource-limited settings, but needs validation in a field setting. Methods DBS samples were collected using fingerstick capillary blood from 143 HBV-infected individuals at Sebeta Health Centre, Ethiopia, covering the total range of quantification from < 2 to > 8 log 10 IU/ml. Plasma samples were collected in parallel using standard venipuncture whole blood. The Xpert ® HBV viral load assay was used to quantify HBV DNA. HBeAg detection was performed using the Alinity i HBeAg assay. DBS and plasma viral loads were compared using linear regression analysis. Stability studies were performed in 10 DBS samples stored at ambient temperature for up to 24 weeks. Results HBV DNA was detected in all 89 DBS samples with plasma HBV DNA above the WHO-recommended decision threshold of 3.3 log 10 (= 2000) IU/ml. A strong correlation (R 2 = 0.90) was observed between plasma and DBS, with a mean difference of 0.23 log 10 IU/ml. DBS had 85.7% sensitivity and 92.9% specificity for the detection of HBeAg. No clinically relevant change of HBV DNA was observed in DBS stored at room temperature up to 12 weeks; however, a reduction of more than 0.5 log 10 IU/ml was observed in 4 of 10 DBS samples at week 24. Conclusions DBS is a reliable sample matrix for HBV DNA quantification and HBeAg detection in resource-limited settings.