Viral Vector Safety Testing Service

Physical Titer

Physical titer calculates the total number of alive and dead viral particles present and is expressed as the number of viral particles per mL (VP/mL), or for AAV as genome copies per mL (GC/mL). Clinical dosing of rAAV therapeutics is usually based on physical titer, thus having accurate quality control methods that determine the amount of vector being administered is important. There are a variety of methods used to determine the physical titer of virus based on quantifying the concentration of viral genomes or viral proteins.

Infectious or Functional Titer

Infectious or functional titer is always more accurate than physical titer because it measures how much virus can infect the target cell. It is always lower than physical titer, typically by a factor of 10 to 100-fold. Functional titer is expressed as transducing units per mL (TU/mL) for lentiviral or retroviral vectors. Adenoviral vector titer is generally expressed as plaque-forming units per mL (PFU/mL) or infectious units per mL (IFU/mL). The latter term is used for viral vectors that do not lyse cell membranes and therefore are not compatible with the plaque assay.

Overall solution

CD BioSciences offers the following viral vector safety testing service services to meet the specific needs of different customers.

Quality Attribute Technique
Potency Physical viral titer DNA hybridization, Real-time PCR (qPCR, ddPCR), NanoSight, HPLC
Functional viral titer Plaque-forming assay, Fluorescence foci assay, TCID50 (end point dilution assay)
  • CD BioSciences uses end-point dilution analysis (TCID50) to measure the titer of infectious virus by quantifying the amount of virus required to kill 50% of host cells or produce a killing cell effect.
  • CD BioSciences uses high performance liquid chromatography (HPLC), which is also a fast method to quantify total virus particles, because the column can separate intact virus particles from other cellular contaminants or virus particle fragments.
  • CD BioSciences uses optical density (A260/280) assay, which can measure the concentration of viral DNA and protein. This is a physical method for measuring the concentration of virus particles (VP).

Our advantages

  • The team of CD BioSciences has a wealth of knowledge and experience. We work with many from all over the world, and our service quality is guaranteed.
  • Our research supervisor and project manager will complete your project on time through open communication channels and meet your requirements.
  • CD BioSciences has established a professional after-sales service team to provide customers with efficient, fast and practical solutions.

Our service items

Project name Viral vector safety testing service
Our services
  • Sterility testing service
  • Endotoxin testing service
  • Mycoplasma testing service
  • Replication competent virus testing service
Product delivery mode We will complete the project on time according to the agreed time, summarize the experimental data and conclusions, and complete the experimental report.
Price Inquiry

Why choose us?

CD BioSciences provides professional viral vector safety testing service to meet the needs of regular customers to identify hits on time and on budget. CD BioSciences relies on world-class cell engineering technology expertise, we provide customers with the best quality one-stop Viral vector safety testing service, including the development of experimental programs according to different experimental needs. Please feel free to contact us for more detailed information, our scientists will tailor the most reasonable plan for your project.


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