Matrix metalloproteinases (MMP) play a crucial role in numerous pathological processes. Because cellular changes may be reflected in body fluids, measurements of MMP in blood have been recommended as noninvasive tools in diagnosis and monitoring of diseases(1). MMP measurements can be affected by the blood sampling procedures, as shown for gelatinase B (EC 3.4.24.25; MMP-9), for which higher concentrations have been noted in serum than in plasma samples(2)(3). However, the impact of the blood sampling process on measurements of many other MMPs has not yet been studied in detail. Our aim was to demonstrate the effect of blood sampling on the concentrations of collagenase-1 (EC 3.4.24.7; MMP-1), stromelysin-1 (EC 3.4.24.17; MMP-3), matrilysin (EC 3.4.24.33; MMP-7), and collagenase-2 (EC 3.4.24.34; MMP-8) circulating in blood. Because the preanalytical impact of blood sampling is well known for gelatinase A (EC 3.4.24.24; MMP-2) and MMP-9(4), we measured these substances for use as comparisons. The study was performed in accordance with the ethical standards of the Helsinki Declaration and was approved by the ethical board of the hospital. All sample donors recruited on a voluntary basis and informed about the objectives of the study provided written informed consent. …
