We assessed the usefulness of zinc and copper serum level changes as acute rejection markers in orthotopic heart transplantation. Mean serum zinc levels occurring without rejection were 74 +/- 1.9 micrograms/dl, whereas with rejection they were 67 +/- 3.2 micrograms/dl (p = 0.056). Mean serum copper levels occurring without rejection were 109 +/- 3.9 micrograms/dl, whereas with rejection they were 116 +/- 6.4 micrograms/dl (p = 0.32). Results of our study show that changes in serum zinc and copper levels are not useful as rejection markers in heart transplantation. Levels of these trace elements can be affected by clinical situation and therapy in heart transplant patients regardless of rejection.