Cell health should always be tested prior to the start of an experiment. Regular visual inspection of the shape and appearance of your cells in culture and just before use will allow you to detect unhealthy cultures at an early stage and ensure that you use healthy cells for your assay. But the health of the cell line cannot be determined by observing the cells under the microscope alone. Even if a cell appears healthy and is viable, it may not be able to proliferate, which may affect the results of your experiment.
Critical parameters for cell health include cell viability and phenotype indicators, such as morphology, cell marker expression, and cell bio functionality. Depending on your objective, other critical parameters could be tested for metabolites, apoptotic markers, stress signals, toxicity markers, or indicators of cell lysis.
You should maintain records of proliferation and associated morphological images which could provide a reference to enable appreciation of changes of time (weeks, months, or years) where cell types may have differentiated following excessive passaging.
Cell lines should be assessed regularly for cell health. In fact, testing a cell population’s viability after each passage serves two purposes:
1. It indicates cell health.
2. It allows one to accurately seed the cells at the right concentration, in preparation for the next experiment.