This document discusses quantitative real-time PCR (qPCR). qPCR allows for quantification of starting DNA amounts using cycle threshold differences. Known DNA standards are used to create a standard curve, which allows quantification of samples so long as they fall within the standard curve range. qPCR is commonly used clinically to quantify transcripts like BCR-ABL, where lower transcript levels indicate better patient outcomes.

1. Quantitative real-time PCR
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2. Qualitative PCR is limited

3. Quantitative real-time-PCR
Taqman probe

4. Handy qPCR definitions

5. Some definitions
Threshold
Cycle Threshold
Cycle number
Log(fluorescence)

6. Cycle threshold differences tell you
relative amounts of starting DNA

7. Known standards are used to create a
standard curve for quantitation

8. Outside of the standard curve,
quantitation is not reliable.

9. Which sample started with the most
target?
1.Red
2.Blue
3.Purple
4.Green

10. Which sample started with the most
target?
1.Red
2.Blue
3.Purple
4.Green

11. Quantities of your transcript
are compared to an internal
control.
We use ABL in qBCR-ABL PCR.

12. Clinical Significance

13. Fewer transcripts is better.
International Randomized Study of Interferon and STI571 (IRIS)
NEJM 2003;348:994-1004; also NEJM 2006;355:2408-2417.