The amount of a proline-serine-threonine phosphatase-interacting protein 1 when measured in blood serum. The trait is Ontology of Biological Attributes term OBA_2043085 (level of proline-serine-threonine phosphatase-interacting protein 1 in blood serum). Also known as: blood serum proline-serine-threonine phosphatase-interacting protein 1 amount.