Ready-to-use ELISA kits are available for the detection of PAI1A, an alias of the protein, serpin family E member 1. The official gene symbol is SERPINE1. The kits can detect several species variants of the protein, including: human, mouse, and primate. The protein, with a mass of 45.1 kDa and length of 402 residues, is reported to be secreted. It is a member of the Serpin family and may be known by other names, including: PAI-1, PAI, serpin E1, serine (or cysteine) proteinase inhibitor clade E (nexin plasminogen activator inhibitor type 1) member 1, endothelial plasminogen activator inhibitor, and plasminogen activator inhibitor 1, and PLANH1.