Jump to content

  • Log in with Facebook Log in with Twitter Log in with Windows Live Log In with Google      Sign In   
  • Create Account

Submit your paper to J Biol Methods today!
Photo
- - - - -

IC50 using microsoft excel


  • Please log in to reply
1 reply to this topic

#1 kentz19

kentz19

    member

  • Active Members
  • Pip
  • 26 posts
1
Neutral

Posted 10 August 2010 - 06:34 AM

hi,

what is the right way of determining IC50 using microsoft excel? I went across several articles that used excel to calculate ic50, and there is one term 'linear interpolation'.I'm not really sure what it is. I just want to know, whether, for all this while i calculate the correct way using excel. What I did was, I transform the concentration values into log, then I construct scatter graph using excel with y-axis=% inhibition and x-axis= log conc. Finally I add trendline and got linear equation y=mx + c. Frm this equation, I substitute y with 50, and get x=log conc. I antilog the value and get the true x value. Is this linear interpolation?? I attach one of the graph and the way I calculate for reference.

Thank you in advance

untitled.JPG

#2 Mycobacterial Madman

Mycobacterial Madman

    member

  • Active Members
  • Pip
  • 10 posts
0
Neutral

Posted 10 August 2010 - 03:32 PM

Sorry I dont use excel to calculate IC50, I use SigmaPlot. However you can check your calculated values online here:

http://www.changbios.../stat/ec50.html

Beware of using a linear trendline, if your inhibition profile is not linear this will give you messed up values. I think you need more high and low concentration points on your graph, so you encompass no inhibition all the way through to full inhibition, 3 points for each is what I aim for to get a good curve for robust IC50 calculation.




Home - About - Terms of Service - Privacy - Contact Us

©1999-2013 Protocol Online, All rights reserved.