Determining Viral Titer by TCID50

The TCID50 (50% Tissue Culture Infectious Dose) assay is a traditional method used by virologists to determine viral titers in both stocks and samples. Many viruses do not form traditional plaques and there may not be tools readily available to determine viral foci by immunolabeling or fluorescent reporters. In these cases, infection is indicated by Cytopathic Effect (CPE), phenotypically indicated by cell rounding, fusing, or other morphological changes. To determine the TCID50 using a label-free technique, full-well images of infected monolayers and controls are captured with the Lionheart™ FX Automated Microscope or Cytation™ Cell Imager Multi-mode Reader.  Stitching and processing steps are applied to facilitate analysis of confluency in each well. Using post-analysis tools in the Gen5™ software, a custom binary CPE factor is calculated for each well and used to calculate the TCID50 using the method of Reed and Muench.


TCID50 Application


Full-well images are captured in brightfield, then stitched and processed as part of a fully-automated Gen5™ imaging protocol




The confluency of each well is calculated and converted to a custom binary CPE factor using optimized Gen5 cellular analysis tools and post-analysis equations



Confluency and CPE factor are reported for individual wells and mean responses to viral dilutions are automatically graphed as part of the TCID50 calculation


Increase assay throughput and performance

BioSpa™ Compatible Assay: Live-cell analysis on up to 8 microplates
The BioSpa Live Cell Analysis System
enables multi-plate kinetic analysis of the
label-free TCID50 when integrated with
Cytation Live Cell Imager



Application Notes





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