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Analyses of human biological materials
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The determination of elements in body fluids and other human biological material can be used as a diagnostic tool in various disorders, for investigation of exposure, and to check administration of metal-based pharmaceuticals.
When studying human exposure to toxic elements in the environment, analysis of human biological material - so-called biological monitoring - provides a complement to analysis of air, water and other environmental samples. An advantage of biological monitoring is that the results reflect uptake of the substance by the organism, which varies between individuals as well as over time in a given individual.
SAMPLE TYPES
The most common sample types used in element analyses are whole blood, serum/plasma and urine. The choice of sample type depends e.g. on how a specific element is metabolised by the organism. Plasma levels are of special interest since this fraction is readily available for tissue uptake. However, certain elements, especially lead and cadmium, bind strongly to red blood cells. Urine levels are generally corrected for dilution by normalisation to creatinine.
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ALS Scandinavia provides accredited analyses of whole blood, serum, plasma, urine, hair and nails.
NATURAL LEVELS
The study of trace elements in human biological material has long been subject to technical limitations. Difficulties are associated with low concentrations, complex sample matrices and small available sample volumes. The technical development of analytical instruments with greater sensitivity and selectivity in combination with improved sample handling has nevertheless enabled determination of a growing number of elements down to naturally occurring levels. A compilation of results from research at the ALS Scandinavia laboratory can be found on www.human-analysis.com.
SEVERAL ELEMENTS SIMULTANEOUSLY
The use of multi-element techniques for simultaneous analysis of several elements allows a large amount of analytical information to be obtained rapidly from small sample volumes. This facilitates e.g. the study of interactions between different elements. Multi-element analysis also permits unprejudiced screening for identification of elements related to non-specific symptoms of deficiency or poisoning.
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STABLE ISOTOPES
Stable enriched isotopes are highly suitable for metabolic studies.
CONTAMINATION RISK
As in all trace element analyses, sampling, preservation and storage techniques must be meticulous in order to prevent contamination and loss. As an example, chromium and nickel can be released from metal syringe needles. Urine, serum, plasma and blood samples must be refrigerated. Urine, serum and plasma should preferably be frozen. However, freezing of whole blood results in destruction of the red blood cells and prevents separate analysis of serum or plasma.
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COMPARISON PROGRAMMES
ALS Scandinavia participates in the ICP-MS Comparison Programme, an ongoing series of analytical comparisons arranged by Le Centre de Toxicologie du Québec (CTQ). Purpose of this programme is to enable laboratories using ICP-MS for biological samples to compare results. To date, ALS Scandinavia has participated in comparative studies on whole blood, serum/plasma, urine, hair, nails, liver and kidney for a large number of metals. For results, please contact the laboratory.
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