PCR and RT-PCR: The Basics
Polymerase Chain Reaction (PCR) amplifies a specific segment of DNA, making millions of copies from a tiny starting sample so it can be reliably detected. RT-PCR (reverse transcription PCR) adds an extra step: it first converts RNA into complementary DNA (cDNA), which is then amplified in the same way. This makes RT-PCR the standard method for detecting RNA viruses and for gene expression studies.
Real-time (quantitative) PCR adds fluorescent detection to every amplification cycle, allowing the amount of target material to be measured as it accumulates, rather than only at the end of the reaction. The cycle at which fluorescence crosses a detection threshold (the Ct value) is inversely related to the amount of starting material: lower Ct values indicate more target was present in the original sample.
Good assay design and reagent quality directly affect sensitivity and specificity. Our molecular diagnostics catalog includes kits validated for both liquid and lyophilised formats, suited to a range of thermocycler platforms.