title: Letter: Collection of blood uncontaminated with Ca, Cu, Mg, or Zn, for trace-metal analysis.
mesh_terms: D001800:Blood Specimen Collection; D004340:Drug Contamination; D008670:Metals / Q000032:analysis*; D014131:Trace Elements / Q000032:analysis*
chemical_list: D008670:Metals; D014131:Trace Elements