38
| 4 | 2011
Klinisk Biokemi i Norden
(
Fortsat fra side 37)
Konklusjon
Vi foreslår å vurdere prøvematerialets holdbarhet ut
fra enkle krav til bias og totalfeil: Holdbarhet krever
at 90%-konfidensintervallet rundt gjennomsnittet i sin
helhet ligger innenfor gjennomsnittlig utgangsverdi
±tillatt bias
og
at alle enkeltverdier ligger innenfor
utgangsverdi ±tillatt totalfeil. På den måten hindrer
vi både at oppbevaring gir for store systematiske end-
ringer og for store endringer i enkeltprøver.
Referanser
1.
Guder WG, da Fonseca-Wollheim F, Heil W,
Schmitt Y, Töpfer G, Wisser H, Zawta B. Qua-
lity of diagnostic samples. Recommandations
of the working group on preanalytical quality
of the German Society for Clinical Chemistry
and Laboratory Medicine. 3rd ed. German
Society for Clinical Chemistry and Laboratory
Medicine: 2010.
2.
ISO Guide 30. Terms and definitions used in
connection with reference materials. 2nd ed.
Geneva: International Organization for Stan-
dardization, 1992.
3.
Tanner M, Kent N, Smith B, Fletcher S, Lewer
M. Stability of common biochemical analytes
in serum gel tubes subjected to various storage
temperatures and times pre-centrifugation.
Ann Clin Biochem 2008;45:375-9.
4.
O’Keane MP, Cunningham SK. Evaluation of
three different specimen types (serum, plasma
lithium heparin and serum gel separator) for
analysis of certain analytes: clinical significance
of differences in results and efficiency in use.
Clin Chem Lab Med 2006;44:662-8.
5.
Thiers RE, Wu GT, Reed AH, Oliver LK. Sample
stability: a suggested definition and method of
determination. Clin Chem 1976;22:176-83.
6.
Leino A, Koivula MK. Stability of chemical
and immunochemical analytes in uncentri-
fuged plasma samples. Ann Clin Biochem
2009;46:159-61.
7.
Fraser CG. Biological variation: From principles
to practice. Washington: AACC Press, 2001.
8.
Gowans EMS, Hyltoft Petersen P, Blaabjerg O,
Hørder M. Analytical goals for the acceptance
of common reference intervals for laboratories
throughout a geographical area. Scand J Clin
Lab Invest 1988;48:757-764.
9.
Nowatzke W, Woolf E. Best practices during
bioanalytical method validation for the charac-
terization of assay reagents and the evaluation of
analyte stability in assay standards, quality con-
trols, and study samples. AAPS J 2007;9:E117-22.
10.
Åsberg A, Bolann B, Mikkelsen G. Using the
confidence interval of the mean to detect sys-
tematic errors in one analytical run. Scand J
Clin Lab Invest 2010;70:410-4.
11.
Hoffman D, Kringle R, Singer J, McDougall
S. Statistical methods for assessing long-term
analyte stability in biological matrices. J Chro-
matogr B Analyt Technol Biomed Life Sci
2009;877:2262-9.
12.
Desirable Specifications for Total Error, Impre-
cision, and Bias, derived from intra- and inter-
individual biologic variation.
-
gard.com/biodatabase1.htm (16.02.2011).
Blodvaxskivling (Hygrocybe coccinea). Foto: Henrik Alfthan
