My experience varies.
It all depends on your luck, no regulations can be found.
My friend's parents applied for a 3-month visit but was told the Consulate receptionist that they needed medical examination. But the same case for my parents they got the visa the next day.
The secenario is that the immigration officer may ask you to be medical examed before he sees your file.
If you are not required to do the M.E. the visa may be granted the next bosiness day.