IPC (Internal PCR Control)
Definition
A non-forensic DNA sequence spiked into the PCR reaction at fixed concentration; a shift in IPC Ct value relative to the expected value indicates PCR inhibition.
- Full name
- Internal PCR Control
- Function
- Non-forensic sequence spiked at fixed concentration
- Signal watched
- Shift in Ct value versus expected
- Indicates
- Presence of PCR inhibition
Common questions
How does an analyst distinguish inhibition from low DNA quantity using the IPC?+
Because the IPC is added at a known fixed amount, its Ct value should be consistent every run. If the sample's target loci amplify weakly but the IPC also shows a delayed Ct, inhibition is the likely cause rather than simply too little template DNA present.
What happens once inhibition is flagged by the IPC?+
The lab typically dilutes the extract to reduce the inhibitor concentration, applies additional purification such as re-extraction or a spin-column cleanup, or adds inhibitor-resistant polymerase mixes before re-amplifying, rather than reporting a failed or partial profile outright.
Related terms
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- GlobalFiler
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- Haematin
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- Humic Acid
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- Identifiler Plus
- Applied Biosystems 16-plex STR kit covering the original 13 CODIS loci plus D2S1338, D19S433, and Amelogenin. Widely used through the 2010s; insufficient...
- Investigator 24Plex QS
- Qiagen 26-plex STR kit with Quality Sensor (IPC) and covering 24 STR loci plus DYS391 and Amelogenin. GO! variant uses increased cycles...
- Low-Copy-Number (LCN) PCR
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- PowerPlex Fusion 6C
- Promega 23-plex STR kit covering all 20 CODIS core loci, all 17 ESS loci, DYS391, and Amelogenin across 6 dye channels.
- Probabilistic Genotyping
- Software-based interpretation of complex DNA electropherograms using continuous statistical models (e.g. STRmix, TrueAllele, ArmedXpert). Generates a likelihood ratio for complex mixtures previously...