I have a piece of software called English words from Latin and Greek. It may be one of the books found on this Google Books page.
Here's what it says about the prefix suf- and kin:
sub-, sus-, suc-, etc. = under, up from under : secretly submerge, submarine, suspend, sustain, succumb, suffer, support
super-, [sur-] = above, over : superhuman, superfluous, surreal, surcease
Psychiatrists and other physicians talk about subclinical symptoms and subclinical disease and subclinical infection. These can (or cannot, it seems) be found in people who are asymptomatic for a host of viral and bacterial infections. The psychiatrists use it to claim that perfectly normal people are bipolar II because they're hypomanic (it only takes one instance of subclinical hypomania to be declared bipolar II (Diagnostic & Statistical Manual of Mental Disorders (DSM)-V).
I've never seen biomed authors use "superclinical" (but there's a place called SuperClinica in Brazil). They generally use /hypo-/ ~ /hyper-/, as in hypermanic -- manic -- hypomanic.