Altered serum element concentrations due to laboratory usage of Vacutainer tubes

Aliquots of a pooled serum sample (bovine) were agitated in Vacutainer tubes (serum or clot tubes) for 0, 2, 8 and 32 hr to determine if Vacutainer tubes had any effect on serum trace element concentrations. The sera were analyzed for Ca, Cu, Fe, Mg, Na and Zn by the inductively coupled argon plasma emission spectrometer. The Zn concentration in sera was significantly increased over time, and the Cu and Fe concentrations were significantly decreased. Most of these artifacts became apparent within the first 2 hrs of exposure to the Vacutainer tubes. Changes in Cu, Mg and Na concentrations were not detected.