# Clarification Regarding DepMap's IC50 Data and Sanger's IC50 Data

**URL:** <https://forum.depmap.org/t/clarification-regarding-depmaps-ic50-data-and-sangers-ic50-data/1220>\
**Category:** Q&A\
**Created:** [February 23, 2022, 5:11pm UTC](https://forum.depmap.org/t/clarification-regarding-depmaps-ic50-data-and-sangers-ic50-data/1220 "2022-02-23T17:11:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![S.David](https://avatars.discourse-cdn.com/v4/letter/s/dfb087/32.png) [@S.David](https://forum.depmap.org/u/S.David)\
**Post date:** [February 23, 2022, 5:11pm UTC](https://forum.depmap.org/t/clarification-regarding-depmaps-ic50-data-and-sangers-ic50-data/1220/1 "2022-02-23T17:11:13Z")

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Hi DepMap,

I am a little confused regarding the information you have on your website and Sanger’s information. I am refering to your Drug sensitivity IC50 (Sanger GDSC1 and GDSC2) data as well as what Sanger has on their website if you go to compounds and look for a specific drug. Usually, Sanger will present a table like the following:

|Number of cell lines screened|913|  
|Maximum IC50 (uM)|2.18e+3|  
|Geometric mean (uM)|34.8|  
|Minimum IC50 (uM)|0.151|  
|Min screening concentration (uM)|0.125|  
|Max screening concentration (uM)|32.0|

Maybe this is due to the fact that I need to research more information on IC50 values, but how can an IC50 value be higher than the max screening concentration? Thanks for your help.

Thanks,  
SD

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**Author:** ![Mustafa\_Kocak](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.depmap.org/mustafa_kocak/32/11_2.png) [@Mustafa\_Kocak](https://forum.depmap.org/u/Mustafa_Kocak)\
**Post date:** [May 23, 2022, 3:49pm UTC](https://forum.depmap.org/t/clarification-regarding-depmaps-ic50-data-and-sangers-ic50-data/1220/2 "2022-05-23T15:49:20Z")

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Hi SD,

The IC50 values are typically computed as the dose that the fitted curve would reach to 50% viability value. For the cases this number falls out of the range of the measured doses it is given based on the extrapolated curve and I don’t think that is a good number to use in any analysis. I would recomment to replace it with either an NA or capping it with a multiple of the maximum measured dose (maybe 2x).

Warmly,  
Mustafa