It usually depends on the company policy.
I believe for sick leaves, we do not count the intervening holidays/weekly offs.
Secondly, there are many companies who include weekly offs if it is sandwiched between two leaves.
For eg: Sat (Leave) - Sun (Off) - Mon (Leave) so 3 leaves would be deducted.
However I have seen HR Manual of a reputed media industry who do not allow to club the leaves as sat-sun or sun-mon also and consider that as 2 days' leaves.
So it all firstly depends on your company's policy.
25th June 2013 From India, Mumbai