Frolic is a playful word with a happy history. It traces back to the Dutch word vroolijk (merry), which in turn evolved from a Middle Dutch combination of vro (happy) and the adjectival suffix -lijc (-ly).
A normal PSA level is considered to be 4.0 ng/mL (nanograms per milliliter of blood). 1  For men in their 50s or younger, a PSA level should be below 2.5 in most cases.  Older men often have slightly higher PSA levels than younger men.
The following are the percentile ranges of PSA levels: 1  0 â 2.5 ng per ml = Low. 2  2.6 â 10 ng per ml = Slightly to moderately elevated. 3  10 â 19.9 ng per ml = Moderately elevated.  20 ng per ml = Significantly elevated.