Why is my Real Time pcr having a high Ct value?

There may be several reasons why the sample Ct value is too high:  

1． The sample RNA degradation is relatively severe, you can run a semi-quantitative to see if this is the reason.  

2． If the RNA is recently extracted and there is no problem with the samples concentration, there may be a problem in the reverse transcription process, you can check whether the reverse transcription kit used is suitable for your genes, and some kits are specially divided into short genes and long genes.  

3. May be there is nucleic acid contamination in the samples, you can treat the samples with DNase.  

4. The concentration of samples and the the primer do not match, it is recommended to adjust to the appropriate concentration according to the instructions.