ECG for risk stratification in patients with pulmonary embolism.

sampling and separation of serum from blood cells. We agree with M. John and K. Jung that we must be aware of pre-analytical problems when analysing the circulating matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1 levels. However, we used only serum samples in our study because we usually use serum samples for clinical examinations in our hospital. Therefore, we think that the comparison of the serum TIMP-1 and MMP-9 concentrations in each patient group is valid. Our results are consistent with serum TIMP-1 and MMP-9 concentrations reported elsewhere [2, 3].