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!

Determination of the lower limit positivity


  • Please log in to reply
1 reply to this topic

#1 p.blaze53



  • Active Members
  • Pip
  • 14 posts

Posted 16 February 2015 - 06:27 AM

Hi! I am new in biostatistics, and I have a question. I ’m analyzing immunohistochemical expression of a protein in different samples. For example, the 56% of cells were positive in Case1, 65% of cells were positive in Case2 and so on. My problem is that I don’t know how to determine the lower limit of the positivity (or threshold) of the analyzed protein in my experiment? What is lower limit when I could say this case is positive yet or negative below that value? Anybody has an idea?

#2 bob1


    Thelymitra pulchella

  • Global Moderators
  • PipPipPipPipPipPipPipPipPipPip
  • 6,706 posts

Posted 16 February 2015 - 12:08 PM

Hmmm, that's a tricky one, and depends entirely on the protein being investigated. For instance the HER2 (herceptin) protein used to stage and grade breast cancers shows as a peri-cytoplasmic membrane ring, and is considered to be positive if more than 50% of the cell membrane stains. This is backed up by functional studies which showed that below this 50%, breast cancers would not respond to the drugs used to treat these HER2+ cancers.


In your case, you need to determine this point, which could be difficult, but have a look in the literature.

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

©1999-2013 Protocol Online, All rights reserved.