I. Population doubling time (PDT)

The population doubling time of a culture is calculated by the following equation:

PDT in hours = ln2 * (hours of culture) / ln(fold change in cell number)

(Note: PDT is an estimate of the cell cycle time of the dividing cells in a culture only when the dividing fraction of new cells approaches 100% and the cell death rate is insignificant.)

To Calculate PDT:

Enter:
  • t1, time in hours when culture started (usually 0)
  • t2, time in hours when culture period ended
  • N1, number of cells in culture at time = t1
  • N2, number of cells in culture at time = t2
t1
t2
N1
N2

Result:

II. Cell Population Doublings

The number of cell population doublings during a period of culture is calculated by the following equation:

Number of cell doublings = ln(fold increase in cell number)/ln2

To calculate Cell Population Doublings:

Enter:
  • N1, Number of initial cells
  • N2, Number of cells at the end of the period of culture
N1
N2

Result:

III. Cumulative Population Doublings (CPD)

A CPD data graph can be generating by calculating the number of cell doublings for a series of consecutive culture intervals and summing the values sequentially.

To generate CPD for a serially passaged culture enter the following data:

Initial Cell Number:

Passage Number Passage Interval Time in Hours Cell Number at End of Passage Interval Transferred Cell Number
1

Result:
Passage Number Hours of Culture CPD




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