1. Background
  2. Data Collection Methods
  3. Data Quality Control
  4. Summary

Example of a standard curve with linear regression results.

Quantification: Absolute vs. Relative

Absolute Quantification: A standard curve is used to quantify DNA copies in samples.

  1. Generate a standard curve by serially diluting a known quantity of a DNA target, then performing qPCR.
  2. Compare CT values from a sample with CT values in the standard curve.

Relative Quantification: Used to report a fold change in gene expression between reference and target genes.

  1. A reference gene (aka housekeeping gene) and a target gene are used to compute the fold change.
    1. ΔCT(treated) = CT(treated target) - CT(treated reference)
    2. ΔCT(control) = CT(control target) - CT(control reference)
    3. ΔΔCT = ΔCT(treated) - ΔCT(control)
    4. Fold change = 2(-ΔΔCT)