050 - Reference intervals
Autor(s): D. Giavarina
Issue: RIMeL - IJLaM, Vol. 2, N. 1, 2006 (MAF Servizi srl ed.)
Page(s): 50-56
The reference interval is the most widely used medical decision-making tool. Reference intervals are used as guidelines when there are no better methods of distinguishing healthy from diseased states. Most often when screening populations for potential disease, the 95% reference interval is commonly use but, if the purpose of reference intervals is to help the clinician interpret the data, in a hospitalized population, values different from the traditional healthy population may be used. The CLSI and IFCC guidelines are useful under their stated conditions, i.e., a truly healthy sample with a minimum of 120 values. When CLSI and IFCC guidelines are not met, then one must use transformations and outlier detection, and consider the robust method or the indirect methods for computing reference intervals. Nevertheless, not all the problems in the definition of a decision level can be achieved with a good, correct and robust procedure for the reference interval computations. Different approaches must be considered, based on clinical finding; the challenge for the next years could be to abandon reporting of normal ranges, rather than to improve their quality.