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.
Quick Answer. A normal PSA blood level is 4 nanograms per milliliter of blood, according to MedlinePlus. Men younger than 50 should have levels below 2 ng/mL. Older men usually have levels above 4 ng/ML. PSA refers to a protein made by the prostate gland called prostate-specific antigen. Continue Reading