Clinical Use of Reference Intervals Derived from Some CALIPER Studies Questioned

摘要

To the Editor:The availability of accurate and appropriate reference intervals is imperative for proper screening, diagnosis, and monitoring of disease. It is therefore with great interest that we read the recent reports (1, 2) by the CALIPER (Canadian Laboratory Initiative for Pediatric Reference Intervals)1 group. The efforts of the CALIPER project to provide these reference intervals for a diverse pediatric population is highly commendable, particularly in view of the substantial challenges of establishing them for this demographic. Apart from the rigors of selecting and collecting samples to establish reference intervals, the analytical quality of the data has to be ensured. It is with regard to these aspects of these studies that we would like to raise certain important concerns.Steroid concentrations are known to change substantially with the time of day when the blood sample is drawn. These samples were drawn over a 24-h period; thus, the within-participant variation in concentrations with time was not taken into account. This limitation is probably the most significant criticism of the CALIPER studies. With regard to the study of Bailey et al. (2), diurnal variation in cortisol is present in healthy children from an …