What is the difference between DHEA and DHEA-S?

[proverbs girl]

What is the difference between DHEA and DHEA-S? My doctor checked my DHEA-S and I thought that was a little strange because isn't that the androgens made from the adrenals? Does that have anything to do with pcos? Do women with pcos have high DHEA-S, just a high DHEA level, or do they have both high DHEA and DHEA-S?