Interventions that are conducted with the PSA-Cap trial are the collection of capillary blood (6 droplets) from the fingertip during regular PSA testing in venous blood. PSA is measured in the serum fraction of both samples (capillary and venous) using the established routine procedure, either immediately or after simulation of common transport conditions (intermediate storage for 24; 72/96 h and 168 h at 22 °C). Control measurements include parameters of cell lysis (LDH, HIL check) and general protein stability (albumin). The patient samples used are anonymized at the source by means of a consecutive series of numbers. The anonymized result groups are compared.