# Difference Between Population Doubling and Passage Number | Population Doubling vs Passage Number

The concept of population doubling can give you a rough estimation of the cell count in a cell culture. Therefore, scientists who perform cell culture experiments can decide on what type of experiment they should perform using population doubling,

## What is Passage Number?

Passage number is a numerical value which defines the number of subcultures performed for a given primary cell culture. The primary cell culture is the first isolate of a cell. Thus, the passage number defines the age of a cell. Passaging of cells results in subcultures of the primary cell culture.

Passaging of cells in a cell culture is essential in order to maintain the viability of the particular cells. Hence, passage number is an important consideration when using cells for experiments. Passage number does not provide any information on the cell count. Cell lines with low passage numbers are generally recommended for experiments as they are considered to be relatively new in comparison to cell lines with high passage numbers.

## What are the Similarities Between Population Doubling and Passage Number?

• Population Doubling and Passage Number are important in determining the quality of cell culture experiments.
• They explain the suitability of cells for a particular experiment.

## What is the Difference Between Population Doubling and Passage Number?

Population doubling refers to the measurement of the time it takes to double the cell population. In contrast, passage number is a value of the number of times a particular cell culture is passaged. So, this is the key difference between population doubling and passage number. The other significant difference between population doubling and passage number is that population doubling leads to the cell count of a particular cell population while passage number leads to the age of the particular cell population.

The below infographic presents more information on the difference between population doubling and passage number comparatively.

## Summary – Population Doubling vs Passage Number

In brief, population doubling refers to the time taken to double the cell count whereas passage number refers to the number of subculturings done to the initial primary culture. Thus, according to these definitions, population doubling is a measure of time whereas passage number is not. However, both measurements play an important role in determining the suitability of cells for a particular assay or an experiment. Thus, this is a summary of the difference between population doubling and passage number.

##### Reference:

1. “Cell Culture – An Introduction.” Cell Culture – Introduction | ABM Inc., Available here.