Intraindividual reference values
Abstract
When a biological quantity examination exhibits a high degree of individuality, developing a strategy for interpreting these values in an individual context can be a useful alternative. Time-series analysis is the appropriate statistical framework to build a model for explanation of the behaviour of laboratory information and to forecast future values. The key concepts in this approach are autocorrelation and withinperson variance. Unfortunately, the powerful tools provided by time-series analysis require many observations, a requisite difficult to meet in every day practice. However, introducing some restrictions in the autocorrelation parameter of the most reliable model, the first order autocorrelation model, and using the average within-person variance from a selected population, it is possible to build predictive reference intervals for an individual, based on only few observations. The most common case is the minimum time series: when there are just two observations. The statistical significance of the change from a previous observation is a problem that arises from both quality control (delta checks) and the interpretative diagnostic fields (reference change limit). Applying the same restrictive criteria, it is possible to develop specific limits for a difference between consecutive observations based on a within-person variance selected from the distribution of variances found in a sample of similar individuals.
Copyright © 2004 by Walter de Gruyter GmbH & Co. KG
Articles in the same Issue
- Editors introduction
- Reference values: from philosophy to a tool for laboratory medicine
- The evolution of the reference value concept
- Normality: the unreachable star?
- Selecting clinically relevant populations for reference intervals
- The IFCC recommendation on estimation of reference intervals. The RefVal Program
- Graphical interpretation of confidence curves in rankit plots
- Partitioning biochemical reference data intosubgroups: comparison of existing methods
- Parametric methods for estimating covariate-dependent reference limits
- Reference regions of two or more dimensions
- Should we maintain the 95 percent reference intervals in the era of wellness testing? A concept paper
- Clinical interpretation of reference intervals and reference limits. A plea for assay harmonization
- Inherent biological variation and reference values
- Intraindividual reference values
- Guideline for the production of multicentre physiological reference values using the same measurement system. A proposal of the Catalan Association for Clinical Laboratory Sciences
- Proposal for guidelines to establish common biological reference intervals in large geographical areas for biochemical quantities measured frequently in serum and plasma
- Reference intervals for plasma proteins: similarities and differences between adult Caucasian and Asian Indian males in Yorkshire, UK
- Diagnostic and epidemiological implications of regional differences in serum concentrations of proteins observed in six Asian cities
- Study of reference values and biological variation: a necessity and a model for Preventive Medicine Centers
- Creation of a low-risk reference group and referenceinterval of fasting venous plasma glucose
- Establishment of a serum thyroid stimulating hormone (TSH) reference interval in healthy adults. The importance of environmental factors, including thyroid antibodies
- Difficulties in establishing reference intervals for special fluids: the example of 5-hydroxyindoleacetic acid and homovanillic acid in cerebrospinal fluids
- Metrological traceability of calibration in the estimation and use of common medical decision-making criteria
- Creation of the necessary analytical quality for generating and using reference intervals
- Analytical quality specifications for common reference intervals
- Design of internal quality control for reference value studies
- The NEXUS vision: an alternative to the reference value concept
- Meetings and Awards
Articles in the same Issue
- Editors introduction
- Reference values: from philosophy to a tool for laboratory medicine
- The evolution of the reference value concept
- Normality: the unreachable star?
- Selecting clinically relevant populations for reference intervals
- The IFCC recommendation on estimation of reference intervals. The RefVal Program
- Graphical interpretation of confidence curves in rankit plots
- Partitioning biochemical reference data intosubgroups: comparison of existing methods
- Parametric methods for estimating covariate-dependent reference limits
- Reference regions of two or more dimensions
- Should we maintain the 95 percent reference intervals in the era of wellness testing? A concept paper
- Clinical interpretation of reference intervals and reference limits. A plea for assay harmonization
- Inherent biological variation and reference values
- Intraindividual reference values
- Guideline for the production of multicentre physiological reference values using the same measurement system. A proposal of the Catalan Association for Clinical Laboratory Sciences
- Proposal for guidelines to establish common biological reference intervals in large geographical areas for biochemical quantities measured frequently in serum and plasma
- Reference intervals for plasma proteins: similarities and differences between adult Caucasian and Asian Indian males in Yorkshire, UK
- Diagnostic and epidemiological implications of regional differences in serum concentrations of proteins observed in six Asian cities
- Study of reference values and biological variation: a necessity and a model for Preventive Medicine Centers
- Creation of a low-risk reference group and referenceinterval of fasting venous plasma glucose
- Establishment of a serum thyroid stimulating hormone (TSH) reference interval in healthy adults. The importance of environmental factors, including thyroid antibodies
- Difficulties in establishing reference intervals for special fluids: the example of 5-hydroxyindoleacetic acid and homovanillic acid in cerebrospinal fluids
- Metrological traceability of calibration in the estimation and use of common medical decision-making criteria
- Creation of the necessary analytical quality for generating and using reference intervals
- Analytical quality specifications for common reference intervals
- Design of internal quality control for reference value studies
- The NEXUS vision: an alternative to the reference value concept
- Meetings and Awards
