Effects of Anticoagulants and Contemporary Blood Collection Containers on Aluminum, Copper, and Zinc Results

Extract

Laboratory analysis is used to evaluate both deficiency and excess of trace elements (1). The intravascular concentrations of many of these elements are maintained within narrow limits. For this reason, preanalytical loss of analyte and spuriously high values attributable to contamination are concerns. Blood collection, processing, and storage before analysis are critical for accurate trace element analysis. Decreased concentrations of analytes may result from adsorption onto collection container surfaces or from the use of anticoagulants that complex metals (2)(3). Sources of contamination include patient clothing and skin; blood collection materials, including needles, anticoagulants, stoppers, serum separators, and glass containers; and particulate matter in laboratory air.

Aluminum, copper, and zinc are three metallic elements commonly monitored by the clinical laboratory. Although aluminum may have a physiological role in the action of a few enzymes, such as succinic dehydrogenase and porphobilinogen synthase, it is typically monitored to evaluate toxicity in patients subjected to hemodialysis for renal failure (3)(4). These patients may be exposed to high aluminum concentrations in their treatment regimen but lack an efficient physiological means to remove this element. Aluminum accumulation may lead to dialysis encephalopathy and osteomalacia. Toxicity is known to occur at concentrations >100 μg/L, although symptoms may occur at 60 μg/L or lower in dialysis patients (3)(5). Because aluminum is ubiquitous and pervasive, contamination is a serious concern for the analytical laboratory. Falsely high concentrations measured in contaminated specimens may affect clinical decisions.