This study summarised the External Quality Assessment Scheme (EQAS) for the biological monitoring of occupational exposure to toxic chemicals, which started in 1995 and continued until a 31st round robin in the spring of 2010. The program was performed twice per year until 2009, and this was changed to once a year since 2010. The objective of the program is to ensure the reliability of the data related to biological monitoring from analytical laboratories. One hundred and eighteen labs participated in the 31st round robin. The program offers 5 items for inorganic analysis: lead in blood, Cd in blood, Mn in blood, Cd in urine, and Hg in urine. It also offers 10 items for organic analysis, including hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid, N-methylformamide, N-methylacetamide, trichloroacetic acid, total trichloro-compounds, trans, trans-muconic acid, and 2,5-hexanedione in urine. Target values were detected by statistical analysis using consensus values. All the data, such as chromatograms and calibration curves, were reviewed by the committee. The results showed that the proficiency rate was <70% prior to the 1st round robin and improved to over 90% for common items, such as PbB and HA, while those for other items still remained at 60-90% and need to be improved up to 90%. In the authors concluded that the EQAS has taken a primary role in improving the reliability of analytical data. A total quality assurance scheme is suggested, including the validation of tech. documentation for the whole analytical procedure.
Authors: Lee, Mi-Young; Yang, Jeong Sun; Kang, Seong-Kyu ;Full Source: SH & W 2011, 2(3), 229-235 (Eng) ;