The reliability of 2,3,7,8-tetrachlorodibenzo-p-dioxin and toxicity equivalence measurements in Missouri residents

This study evaluates the reliability of serum measurements of 2,3,7,8-tetra chlorodibenzo-p-dioxin (TCDD) and toxicity equivalence (TEQ) in individuals with no prior exposure to TCDD or dioxin-like compounds above background l evels. Reliability was measured over three time-periods in the same individ uals, TCDD and TEQ were measured in 127 and 128 participants. The values de clined during the testing periods. Reliability coefficients for TCDD was 0. 69 and for TEQ 0.91 but increased to 0.79 and 0.92, respectively, after rem oval of three outlying cases. Study results show good reliability over 22 m onths suggesting a consistency in the uptake and excretion of TCDD and othe r dioxin-like compounds. (C) 2000 Elsevier Science Ltd. All rights reserved .