Detection of HBV-DNA in Dried Bloodstains on Filter Paper by Nested Polymerase Chain Reaction

Objective: To describe the technical performance of nested PCR for identifying hepatitis B viral (HBV) DNA. Methods: Hepatitis B viral DNA was extracted from a dried bloodstain on filter paper by a Chelex-100 method. Then the DNA fragment was amplified by nested polymerase chain reaction (PCR). The sensitivity and specificity of this method were also analyzed. The positive rate of the nested PCR-based method was compared with that of the enzyme-linked immunosorbent assays (ELISA) method. Results: The lowest detection limit of the test was 5 copies of HBV DNA per μL by this method. McNemar’s test showed that the difference between the positive rates of these 2 methods was not statistically significant (P =0.289, P >0.05). Hepatitis B viral test results showed a good concordance between these 2 methods (kappa=0.727). Conclusion: A very small amount of the dried blood sample is required for the detection, which could overcome the shortage of the normal ELISA method that requires a relatively large amount of fresh blood samples.