BioLT

Worked Example

No-RT Control Example for RNA qPCR

Worked example for using no-RT controls to distinguish true cDNA signal from genomic DNA carryover.

Scenario

A qPCR target amplifies in both the reverse-transcribed sample and the no-RT control.

The example focuses on deciding whether the signal can still be interpreted or whether sample preparation must be reviewed first.

Inputs to confirm

Ct values for RT-positive and no-RT reactions.

Primer design context, especially whether primers span exon junctions when applicable.

Whether DNase treatment or genomic DNA removal was performed.

How a researcher would use the result

Compare no-RT signal to the true sample signal before calculating fold change.

If the no-RT control is close to the sample Ct, interpret expression cautiously and review RNA cleanup or primer design.

Common failure points

Ignoring no-RT amplification because the sample Ct looks strong.

Using a reference gene without checking genomic DNA sensitivity.

Treating DNase treatment as guaranteed rather than verified.