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.

Flask area

A finite measured or assumed value greater than or equal to 5e-324, expressed in cm^2.

Occupied area

A finite measured or assumed value greater than or equal to 0, expressed in cm^2.

The implementation follows this calculation rule: Compute the percentage of a culture vessel surface covered by cells from occupied and total flask areas.^[1]

Confluence

The calculated confluence in %.

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.

• Seeding Density

  Compute cell seeding density in cells per square centimeter from a cell count and growth area.

• Specific Growth Rate

  Calculate the specific growth rate in inverse hours from two counts.

• Cell Viability %

  Calculate the viability percentage from viable and total cell counts.