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:
- 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:
- 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 |
---|