Cell viability is the ratio between live and dead cells. It is typically counted using imaging methods that calculate the number of total cells and use special cell stains or dyes to color dead cells for differentiation. Cell viability assays are used throughout cell culture to ensure proper conditions are met and maintained and can be used to determine the effect of drug candidates on cells.

Cell proliferation assays measure the change in a number of cells either as an endpoint measurement or monitored over time. The division of cells increases the total number of cells in a sample, which can be activated or suppressed, and plays a vital role in understanding the growth of tissues and cell cultures, Cell proliferation may be measured with IHC/ICC, ELISA, Flow Cytometry, or Spectrophotometrically.

Cytotoxicity assays are able to determine whether the integrity of cell membranes is compromised, which leads to downstream effects called cytotoxic insults that can reduce cell proliferation or induce cell apoptosis. In the screening process of drug discovery, cytotoxicity of healthy cells is undesired and can be used to eliminate candidates from screening libraries, but cytotoxicity of rapidly dividing cancerous cells is desired and can constitute a “hit” for a new compound. Cytotoxicity assays are also useful in T cell killing assays for the immune cell-mediated killing of tumor cells.

Cell death primarily occurs through three mechanisms: apoptosis, autophagy, and necrosis. Apoptosis is the regulated and controlled cell death that happens naturally in an organism, which is necessary to maintain proper growth and development. Autophagy is the process of ubiquitinating and degrading unwanted proteins via the lysosomal pathway. Necrosis is characterized by the loss of cell membrane integrity which can be both programmed and accidental.

The characterization of cell death mechanisms is important to understanding either cytotoxic or cytoprotective effects of pharmacological agents.

Cellular metabolism is governed by the metabolic pathway, the various biochemical reactions that happen in living organisms. The aim of these assays is to study mechanisms of metabolism such as oxygen, lipids, carbohydrates, and cholesterol.

Cell migration is the directed movement of a single cell or a group of cells in response to chemical and/or mechanical signals. It is a fundamental cellular process that occurs throughout life, starting during embryonic development and continuing until death, and at times it can contribute to pathogenic states in disease. Common studies include cell chemotaxis, wound healing and cell invasion assays.

Cell signaling pathways transmit external and internal stimuli to the various functions of the cell. Signal transduction is carried out by proteins and enzymes. Cell signaling errors can cause diseases such as cancer, autoimmune disorders and diabetes.