# Difference between semi-q and qPCR - (Sep/24/2008 )

I am really ashamed that I don't know this, because I'm working a lot with semi-quantitative real time pcr. Can someone tell me the difference betweem semi-quantitative real time pcr and quantitative real-time pcr? To what criteria do you have to meet to make a real-time pcr quantitative in stead of semi-quantitative?

Thanks!

I just had this discussion with a new student in our lab, so I'll take a stab at it.....

The primary difference is in the set up of the assay. qPCR is much like an ELISA, in thast it requires a standard curve using a known number of your target molecules in each step of the curve. Again, much like an ELISA, you can interpolate your RealTime data for your experimental samples to the that of the standard curve and get a pretty precise estimate of copy number.

Semi-qPCR is a slightly different beast, wherein rather than using a standard curve, you estimate target copy number relative to another transcript (e.g. b-actin, GAPDH, 18srRNA).

If you'd like a more detailed dissection of the two, post again.

The primary difference is in the set up of the assay. qPCR is much like an ELISA, in thast it requires a standard curve using a known number of your target molecules in each step of the curve. Again, much like an ELISA, you can interpolate your RealTime data for your experimental samples to the that of the standard curve and get a pretty precise estimate of copy number.

Semi-qPCR is a slightly different beast, wherein rather than using a standard curve, you estimate target copy number relative to another transcript (e.g. b-actin, GAPDH, 18srRNA).

If you'd like a more detailed dissection of the two, post again.

I figured it would be something like that, I was actually thinking that for really quantitative you should be able to put a SI-unit behind it.