Monitoring the effects of test compounds in the context of the cell,  the fundamental physiologic unit of life, produces more reliable results and therefore allows for better decision making during drug discovery and development. The ability to observe and quantify biological responses within living cells provides a powerful approach to complement and expand upon the data obtained from the biochemical and biophysical assays that are frequently used during the drug screening and hit-to-lead processes. The combination of target-compound binding and biological readout data provides a more complete picture for more confident decision making,  and is fully in-line with the orthogonal approach to drug discovery and development that is increasingly demanded by the regulatory authorities.

Key application areas include:

• Basic research
• Functional and chemical genomics
• Target selection & validation
• Primary & secondary screening
• Lead optimization
• Toxicity testing

Advantages of HCS in drug discovery:

• Provides direct biological readout of compound action
• Yields much more information than traditional in vitro 
  methodologies
• Ability to measure multiple parameters simultaneously in
  the same cell enables identification of potential new
  interactions, on-target and off-target effects
• Automated, high-throughput imaging systems provide
  high data quality and reliability (e.g. multiple replicates
  and  dose-response relationships)
• Flexibility and adaptibility during development process
  - images can be re-interrogated with additional analysis
  methods if new questions arise
• Enables phenotypic screening in cases where detailed
  target knowledge has not yet been acquired