This variable is only available in MAP and MARS.
Matrix metallopeptidase 9 (MMP9) level is quantified from serum samples using highly sensitive multiplexed sandwich enzyme-linked immunosorbent assay (ELISA) arrays by Endogen Searchlight technologies (Billerica, MA). See the inflammatory marker subcategory description for more information.
This variable is expressed in ng/mL and is log transformed.