What are the differences between absolute and relative quantification?

*Absolute quantification determines the absolute number (i.e., number of copies) of a target using a standard sample that has a known number of copies.
*Relative quantifications allow a relative comparison between samples.

Typically, using relative quantification, a target gene to be quantified and a reference gene (e.g., a housekeeping gene) are simultaneously assayed for the purpose of correction (normalization). Relative quantification provides the difference in expression level in the unknown sample compared with the control sample.

Real-time PCR products