Calculating bone-lead measurement variance.
The technique of (109)Cd-based X-ray fluorescence (XRF) measurements of lead in bone is well established. A paper by some XRF researchers [Gordon CL, et al. The Reproducibility of (109)Cd-based X-ray Fluorescence Measurements of Bone Lead. Environ Health Perspect 102:690-694 (1994)] presented the currently practiced method for calculating the variance of an in vivo measurement once a calibration line has been established. This paper corrects typographical errors in the method published by those authors; presents a crude estimate of the measurement error that can be acquired without computational peak fitting programs; and draws attention to the measurement error attributable to covariance, an important feature in the construct of the currently accepted method that is flawed under certain circumstances.
Todd
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Mount Sinai School of Medicine, Department of Community and Preventive Medicine, New York, New York 10029, USA. todd@mssm.edu
D000704:Analysis of Variance; D001699:Biometry; D001842:Bone and Bones / Q000737:chemistry*; D002106:Cadmium Radioisotopes; D005453:Fluorescence; D006801:Humans; D007854:Lead / Q000032:analysis*; D014965:X-Rays
D002106:Cadmium Radioisotopes; D007854:Lead