Professional paper
Quality Control (QC) of clinical and toxicological analyses - recommended model for the Yugoslav QC programme on lead and cadmium in blood
S. Telišman
; Institut za medicinska istraživanja i medicinu rada, Zagreb, Hrvatska
Abstract
The necessity for quality assurance of the clinical and toxicological analyses of biological specimens is emphasized, and the basic characteristics of different models for the quality control (QC) programmes are discussed. Based on the experience gained by participating in various international QC programmes (British National External Quality Assessment Scheme, and QC Programme of the Commission of the European Communities for blood lead; UNEPJWHO QC for blood lead and cadmium; Centers for Disease Control, U. S. A., Proficiency Testing Program for protoporphyrin in blood), the model for the QC programme on blood Pb and Cd analyses in Yugoslavia is recommended. This model includes periodical distribution, at least every two months, of two blood samples with known »true« concentrations of Pb and Cd (»Internal Quality Control« - IQC samples) together with two blood samples with Pb and Cd concentrations unknown for the participating laboratories (»External Quality Control« - EQC samples). At least every six months the distribution of two IQC samples together with six EQC samples (covering the concentration range of 100-800 µg/l for Pb, and 1-20 µg/l for Cd in blood) is considered the most appropriate. All samples should be immediately analysed In the participating laboratories, and the results sent for evaluation to the coordinating institution within 10 days of receiving the samples. The relative advantage of such a combined approach (based on different QC models) is expected to give optimal information on both current and long-term variations in precision as well as accuracy. It is considered indispensable that blood Pb and Cd analyses should be performed only in laboratories with an acceptable performance verified by participation in the QC programmes. The coordinating institution, organizing the QC programme (including preparation and distribution of biological samples, evaluation of results by comparison with the reference »true« values, and providing suggestions on improvement of analyses), should invariably be included in one or more international QC programmes for the specified analyses, and should have highly skilled personnel, adequate (expensive) equipment and experience for such analyses. The necessity of organizing such a programme in Yugoslavia is essential for application of the WHO recommendations on health-based limits in occupational exposure to lead and cadmium (WHO, 1980).
Keywords
Hrčak ID:
158060
URI
Publication date:
7.10.1983.
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