[Trace elements in biological materials. Preanalysis safeguards].

In order to obtain objective information from estimations of trace elements (Al, As, Cd, Cr, Co, Cu, Pb, Li, Mn, Hg, Ni, Se, Zn) on deficiency or intake beyond the toxic limit it is necessary to pay attention among others also to preanalytical safeguarding, i.e. obtain all relevant information on the patient, ensure proper selection of material and sampling time, proper sampling and safeguarding the sample before the estimation proper. If the above rules and principles are respected, possible significant distortion on the results, which can be caused e.g. by contamination of the sample, can be prevented.