usually background checks complete when they send the medical request and from the point in time they recieve your medicals security checks start......background checks can take any time from 3 to 6 months (avg times)... if the status of your app is in process (eCAS) than that means you atleast meet the points criteria.
i applied in 2005
imy application transfered in june,2009
submitted all document in december 2010
i asked embassy they told me under review due background check
is it possible to do background checcks befour medical
how long it take
it mean they finish assistemnt my application
it is postive sign