Valid analytical performance specifications for combined analytical bias and imprecision for the use of common reference intervals

Per Hyltoft Petersen, Flemming Lund (Lead / Corresponding author), Callum G. Fraser, Sverre Sandberg, György Sölétormos

Research output: Contribution to journalArticle

Abstract

Background: Many clinical decisions are based on comparison of patient results with reference intervals. Therefore, an estimation of the analytical performance specifications for the quality that would be required to allow sharing common reference intervals is needed. The International Federation of Clinical Chemistry (IFCC) recommended a minimum of 120 reference individuals to establish reference intervals. This number implies a certain level of quality, which could then be used for defining analytical performance specifications as the maximum combination of analytical bias and imprecision required for sharing common reference intervals, the aim of this investigation.

Methods: Two methods were investigated for defining the maximum combination of analytical bias and imprecision that would give the same quality of common reference intervals as the IFCC recommendation. Method 1 is based on a formula for the combination of analytical bias and imprecision and Method 2 is based on the Microsoft Excel formula NORMINV including the fractional probability of reference individuals outside each limit and the Gaussian variables of mean and standard deviation. The combinations of normalized bias and imprecision are illustrated for both methods. The formulae are identical for Gaussian and log-Gaussian distributions.

Results: Method 2 gives the correct results with a constant percentage of 4.4% for all combinations of bias and imprecision.

Conclusion: The Microsoft Excel formula NORMINV is useful for the estimation of analytical performance specifications for both Gaussian and log-Gaussian distributions of reference intervals.

Original languageEnglish
Pages (from-to)612-615
Number of pages4
JournalAnnals of Clinical Biochemistry
Volume55
Issue number5
Early online date30 Jan 2018
DOIs
Publication statusPublished - 1 Sep 2018

Keywords

  • Allowable bias
  • allowable imprecision
  • combined bias and imprecision
  • Gaussian and ln-Gaussian distributions
  • reference interval

Fingerprint Dive into the research topics of 'Valid analytical performance specifications for combined analytical bias and imprecision for the use of common reference intervals'. Together they form a unique fingerprint.

  • Cite this