Hello

Basically, ∆Ct is the difference in Ct values for your gene of interest and your housekeeping gene for a given sample. This is to essentially normalise the gene of interest to a gene which is not affected by your experiment.

Using the ∆∆ Ct formula to calculate gene expression.

To use the ∆∆ Ct method, you require Ct values for your gene of interest and your housekeeping gene for both the treated and untreated samples.

https://toptipbio.com/delta-delta-ct-pcr/

https://www.researchgate.net/post/What_is_the_theory_behind_the_Delta_Delta_Ct_method

Good Luck

Hi Amanda

As answered by Alkarim, delta ct is the difference in ct values of ur gene of interest and your endogenous control grnerally GAPDH, b-Actin etc. Now delta delta ct is the difference between delta ct of treated sample and control sample. This value finally used to calculate fold change.

Hope this answers your query.

This might be interesting..

Enferm Infecc Microbiol Clin. 2018;36(6):332–335

For gene expression studies it's needed to perform delta delta ct method and calculate the log-fold changes between the housekeeping gene and gene of interest..