Use this calculation for cell-culture or microscopy observations collected with one counting rule, assay gate, calibration, and unit convention. It is suited to documenting dilution, growth, labeling, geometry, or population fractions.

Apoptotic cells

An integer count greater than or equal to 0.

Mitotic cells

An integer count greater than or equal to 0.

The implementation follows this calculation rule: Compute the apoptotic index as the ratio of apoptotic cells to mitotic cells.^[1]

Apoptotic index

The calculated apoptotic index.

Counts and fluorescence measurements can be biased by clumping, debris, segmentation, gating, background signal, saturation, sampling fields, or unequal viability. A calculated percentage does not identify the biological mechanism behind a change. Ratios and percentages become unstable when their denominator is small, uncertain, or defined differently between samples.

Retain representative images or cytometry plots and include biological replicates. Orthogonal viability, proliferation, apoptosis, or direct counting assays can distinguish effects that a single cell metric conflates.

• M Phase Percentage

  Compute the mitotic fraction of a cell population as a percentage of cells in M phase.

• Necrotic Index

  Compute the percentage of necrotic cells in a counted cell population.

• Apoptosis %

  Calculate the apoptosis percentage from apoptotic and total cell counts.