NATrol Nucleic Acid Human Hepatitis B Virus (HBV) Standards (1ml). NATrol products are prepared from highly purified infectious viruses, isolated from either cell culture or the plasma of infected individuals. Once purified, the virus is chemically and enzymatically treated to alter its surface proteins. This treatment results in a completely intact viral particle that is unable to bind, penetrate or infect a host cell. This particle while modified on its surface, still retains a complete viral genome in its core, making it the ideal control for all steps of amplification assays.