"Serum zinc" refers to the amount of zinc present in the liquid part of the blood. It is a measure used to check the levels of zinc in the body, which is an important mineral for various bodily functions. Full definition
However, having serum zinc levels checked when other diagnostic avenues have been exhausted may not be unreasonable, at least until such time as the relationship is better defined. (hari.ca)
Low serum zinc in pregnant women is associated with birth complications such as low birth weight. (parsleyhealth.com)
Low zinc — Low serum zinc has been shown to possibly contribute to acne. (mamanatural.com)