# pfaffl method - (Feb/19/2008 )

Hi,
I'm reading this tutorial http://pathmicro.med.sc.edu/pcr/realtime-home.htm and I was wanting to try the Pfaffl method of quantitation in order to get the efficiency of amplification.
However, the last paragraph of the "Pfaffl method" section states that "The slope of this graph is a measure of efficiency, and can be readily used to calculate efficiency" but the slope of the graph (shown on the left next to that paragraph) has a slope of -3.488. How did they calculate an efficiency of 93.5 from that?

Thanks

Sean

-seangbrown-

QUOTE (seangbrown @ Feb 19 2008, 11:55 AM)
Hi,
I'm reading this tutorial http://pathmicro.med.sc.edu/pcr/realtime-home.htm and I was wanting to try the Pfaffl method of quantitation in order to get the efficiency of amplification.
However, the last paragraph of the "Pfaffl method" section states that "The slope of this graph is a measure of efficiency, and can be readily used to calculate efficiency" but the slope of the graph (shown on the left next to that paragraph) has a slope of -3.488. How did they calculate an efficiency of 93.5 from that?

Thanks

Sean

Here's the paper, I think it's described quite well. If could also try and dig out some old excel sheet, where the values are calculated that way, if that helps you further...

-dedee-

QUOTE (dedee @ Feb 19 2008, 10:21 AM)
QUOTE (seangbrown @ Feb 19 2008, 11:55 AM)
Hi,
I'm reading this tutorial http://pathmicro.med.sc.edu/pcr/realtime-home.htm and I was wanting to try the Pfaffl method of quantitation in order to get the efficiency of amplification.
However, the last paragraph of the "Pfaffl method" section states that "The slope of this graph is a measure of efficiency, and can be readily used to calculate efficiency" but the slope of the graph (shown on the left next to that paragraph) has a slope of -3.488. How did they calculate an efficiency of 93.5 from that?

Thanks

Sean

Here's the paper, I think it's described quite well. If could also try and dig out some old excel sheet, where the values are calculated that way, if that helps you further...

Hi, thanks that paper was very useful. I prefer to know how it was derived but I also found this link. Efficiency for dummies.

http://www.stratagene.com/techtoolbox/calc..._slope_eff.aspx

-seangbrown-