Real-time polymerase chain reaction (Real Time-PCR), also called quantitative real time polymerase chain reaction (qPCR), is a molecular biology technique based on the PCR, and used to amplify and simultaneously quantify DNA strands. For one or more specific sequences in a DNA sample, Real Time-PCR enables both detection and quantification. The quantity can be either an absolute number of copies or a relative amount when normalized to DNA input or additional normalizing genes.

There are two subtypes of Real Time-PCR:

Probe-based (TaqMan PCR) and intercalator-based (SYBR Green) method

Real Time-PCR Application:

1.  Diagnostic use:

For example, Real Time-PCR can be applied in fields of infectious disease (newly emerging flu etc.), cancer (eg p53 gene), genetic abnormalities.

And either microbiological tests in food safety, water quality control
2.  Research tool:

Molecular biology research to quantify levels of gene transcription and thus expression, which might be response of pharmacological stimuli on a cell culture or a normal time-point in life cycle.