The Internal Control represents a second amplification reaction taking place in parallel to the target amplification (mycoplasma) in the same PCR reaction tube. The appearance of the internal control amplicon indicates that the conditions are PCR-permissive (no inhibition of the PCR). The Internal Control DNA is therefore a useful validation tool that helps ruling out false negatives. In the VenorGeM kits, the internal control competes weakly with the target amplification reaction. As a result, a strong amplification (e.g. strong contamination) of the target DNA may lead to failure of the internal control amplification. A missing internal control is therefore a perfectly normal scenario in case of heavily contaminated samples or very efficient PCR amplifications. Consequently, the results of the internal control become irrelevant for positive PCR reactions.