M. Reponen (University of Eastern Finland), J. Kuparinen (University of Eastern Finland) and N. Robinot (International Agency for Research on Cancer) are acknowledged for technical assistance. S. Keppo (Koponen+Hildén) is acknowledged for the technical development of the Plasma Benchmark visualization tool. The University of Eastern Finland mass spectrometry laboratory is supported by Biocenter Finland and Biocenter Kuopio.