What is the purpose of an amplification control in PCR?

The purpose of an amplification control in PCR is primarily to distinguish between a true negative result and an amplification failure. This is crucial in molecular diagnostics because it helps confirm whether the failure to detect a target sequence is due to the absence of the target DNA in the sample or if it resulted from problems within the PCR process itself.

An amplification control is typically a known template that is included in the PCR reaction. If the amplification control yields a positive result, it indicates that the PCR conditions were effective and functional, confirming the reliability of the assay. Conversely, if the control does not amplify as expected, it suggests that there may be issues with the PCR reagents, conditions, or the thermal cycler, leading to a false negative for the actual test samples.

While an amplification control can indirectly provide insights into reagent quality and potential contamination issues, its primary role is clearly linked to confirming the validity of the PCR results relative to the target sequences being tested.