What is the role of inhibition controls in qPCR-based DNA testing?

• A. They monitor PCR inhibition; if inhibition is detected, labs may adjust reaction conditions or re-purify samples
• B. They replace the need for positive controls
• C. They predict contamination sources in the lab
• D. They determine the exact DNA sequence

Answer: (D)

In qPCR-based DNA testing, substances in samples can inhibit the polymerase, leading to false negatives. An inhibition control is included to signal whether the reaction is being affected by such inhibitors. If the control shows poor amplification or a shift in amplification timing, it indicates inhibition, and labs may adjust reaction conditions, dilute or purify the sample, or otherwise modify the protocol to remove the inhibitors. This ensures that a negative result for the target isn’t simply due to inhibition affecting the assay.

It doesn’t replace positive controls, which verify that the assay can detect the target when present; it doesn’t predict lab contamination sources; and it doesn’t provide DNA sequence information.