SharePoint Result source based on query sting value

I have a query string (region) in my url, i have to read region value and pass to result source.

Result source will be: 

path:"https://SP2013" SPContentType=MyList owstaxIdMyColumn1MMD:{Term.Id} owstaxIdMyColumn2MMD:Link isActiveOWSBOOL=1 -owstaxIdRegion:{UK} OR owstaxIdRegion:{Request.region}

Basic code to read query string values in result source:
<ManagedPropertyofColumnNameinList>:{Request.<query string name>}