English Abstract This report describes the results of a WHO-coordinated
interlaboratory comparison study on the analysis of dioxins and PCBs in
mother's milk and human blood. The study is biannually organised by the
WHO, Regional Office for Europe (Copenhagen) and is aiming at the
identification of laboratories capable of the analysis of dioxins and
related compounds at a good, internationally accepted standard. In the
present study, nineteen laboratories from Europe and North- America have
participated for dioxins in mother's milk, sixteen for dioxins in blood and
ten and sic for the analysis of PCBs in mother's milk and human blood,
respectively. The study consisted of the analysis of three different pools
of milk and blood, two of which contained added PCDD/Fs. One of the pools
was sent after the results of two previous pools have been reported (test
for reproducability). Results were evaluated on the basis of statistical
analysis in terms of repeatability, reproducibility and accuracy. In
general, coefficients of varation (CV) were better for analysis in mother's
milk than for the lower levels in blood. Limits for the qualification of
methods were average coefficients of variation of < 20% for analysis of PCBs
in milk and blood, <30% for dioxins in milk and <40% for dioxins in blood.
All our four methods have been qualified. In the final ranking of
laboratories, RIVM-LOC methods scored first positions for PCBs and dioxins
in milk and for PCBs in blood and a third position for the analysis of
dioxins in blood. The average CVs were 12.4, 3.3, 8.7 and 11,3% for
analysis for PCBs and dioxins in milk and blood,
respectively.
