Application of Molecular Diagnostic Techniques for Viral Testing

Cobo, Fernando

The branched or bDNA signal amplification system consists of a series of hybridization steps resulting in a "sandwich" complex of probes and target sequence with a branched structure [11] . In this technique, multiple targetspecific probes are used to capture the nucleic acid onto the surface of a microwell plate. The initial step in a bDNA assay is to ensure that viral particles have been disrupted and that viral RNA is present for analysis. Target-specific oligonucleotides are then hybridized to the target nucleic acid, and other regions hybridize to multiple bDNA amplifier molecules that create a branched structure. Finally, the bDNA signal is the chemiluminiscent product of the reaction [11] . The signal in the bDNA assay is proportional to the number of labeled probes bDNA assays for the quantitation of hepatitis C virus (HCV) RNA, hepatitis B virus (HBV) DNA and human immunodeficiency virus type 1 (HIV-1) RNA are commercially available (Bayer HealthCare, Diagnostics Division, Tarrytown, N.Y.).