INTRODUCTION In Italy, the current legislation for contaminants in soils provides two land uses: residential/public or private gardens and commercial/industrial; there are not specific reference values for agricultural soils, even if a special decree has been developed and is currently going through the legislative approval process. The topic of agricultural areas is relevant, also in considera...

Correcting for measurement error when estimating the density of a routinely collected biomedical variable is an important issue when describing reference values for both healthy and pathological states. The present work addresses the problem of estimating the density of a biomedical variable observed with measurement error without any a priori knowledge on the error density. Assuming the availa...

During the first trimester of pregnancy, thyroid-stimulating hormone (TSH) >2.5 mIU/L has been suggested as the universal criterion for subclinical hypothyroidism. However, TSH levels change continuously during pregnancy, even in the first trimester. Therefore the use of a fixed cut-off value for TSH may result in a different diagnosis rate of subclinical hypothyroidism according to gestational...

PURPOSE To establish reference values for Health Related Quality of Life (HRQoL) in a Dutch rehabilitation population, and to study effects of patient characteristics, diagnosis and physical activity on HRQoL in this population. METHOD Former rehabilitation patients (3169) were asked to fill in a questionnaire including the Dutch version of the RAND-36. Differences between our rehabilitation ...

Patients’ blood test results are different from one another hence Physicians need a reference measure that they can compare to in order to make the correct clinical decisions. These reference measures, obtained from a sample group in the healthy population, are the “normal ranges” for a specific measure. However normal ranges need to be established only for healthy individuals but also for spec...

The average.of.normals quality-control method is examined mathematically. Two modifications are proposed. After modification, the essential unchanged feature of the method is the idea of censoring the laboratory test results so that only means of test values inside the normal range are plotted on the quality-control chart. Several limitations of the modified method are discussed, and I conclude...

Analytical, within-subject, and between-subject components of variation were estimated for 26 clinical chemistry analytes from duplicate analyses of 10 specimens collected from 27 healthy elderly subjects over a period of 20 weeks. Within-subject variations were similar to those generated previously by us in younger subjects. We conclude, therefore, that homeostasis is not compromised by age al...