PCR Controls
Molecular Diagnostics
(MDx) Review 558
CONTROL DESCRIPTION PURPOSE EXPECTED REACTION
Positive control
Negative control (contamination
control, reagent blank, or no
target control)
Negative template control
Internal control (amplification
control)
Target sequence detected
Target sequence not detected
Target sequence not detected
Housekeeping gene detected
Contains nucleic acid
sequence of interest
Contains all PCR components
except DNA
Contains DNA but not
target DNA
Contains 2nd set of primers
& unrelated target (house-
keeping gene or other nucleic
acid target introduced in
sample before nucleic acid
extraction or during PCR)
Ensures that polymerase is active,
primers & thermocycler working
properly.
Checks for contamination with
target DNA or amplicon from
previous amplification.
Ensures that primers aren’t bind-
ing to wrong DNA sequences.
Demonstrates that PCR is working.
Differentiates true neg from false
neg due to amplification failure.
Detects PCR inhibitors.
