Abstract
The first part of this paper discusses some critical factors in planning and evaluation of isochronous stability studies. Recommendations on the number of time-points, number of items, and number of replicates to be measured on each unit are given. In general, more than two time-points should be used. The effect of batch heterogeneity can be eliminated by spreading the results over more units. An approach for combining two or more isochronous stability studies is developed in the second part. This approach includes a potential correction of the earlier stability study, pooling of data of the stability studies, and an uncertainty evaluation taking into consideration the uncertainty of the initial correction. The statistical basis for this approach is developed and equations for evaluation of the uncertainty of stability of the combined study are given.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Guidelines for the production and certification of BCR reference materials (1997) Document BCR/01/97, European Commission, DG XII-5-C (SMT-Programme)
General requirements for the competence of reference material producers, ISO Guide 34 (2000)
Reference materials—contents of certificates and labels, ISO Guide 31 (2000)
Lamberty A, Schimmel H, Pauwels (1998) Fresenius J Anal Chem 360:359–361
Lewis SM (1995) Preparation and certification of a reference material of haemoglobincyanide for standardization of blood haemoglobin measurement—CRM 522. European Commission. Office for Official Publications of the European Communities, Luxembourg, EUR 16101 EN, p 56
Rauret G, Lopez-Sanchez JF, Bacon J, Gomez A, Muntau H, Quevauviller P (2001) Certification of the contents (mass fractions) of Cd, Cr, Cu, Ni, Pb and Zn in an organic-rich soil following EDTA and acetic acid extraction procedures—BCR-700. European Commission. Office for Official Publications of the European Communities, Luxembourg, EUR 19774 EN, p 61
Van der Veen AMH, Linsinger TPJ, Lamberty A, Pauwels J (2001) Accred Qual Assur 6:257–263
Linsinger TPJ, Pauwels J, Lamberty A, Schimmel H, Van der Veen A, Siekmann L (2001) Fresenius J Anal Chem 370:183–188
Van der Veen AMH, Pauwels J (2000) Accred Qual Assur 5:464–469
Van der Veen AMH, Linsinger TPJ, Lamberty A, Pauwels J (2001) Accred Qual Assur 6:257–263
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Linsinger, T.P.J., van der Veen, A.M.H., Gawlik, B.M. et al. Planning and combining of isochronous stability studies of CRMs. Accred Qual Assur 9, 464–472 (2004). https://doi.org/10.1007/s00769-004-0818-x
Received:
Accepted:
Published:
Issue date:
DOI: https://doi.org/10.1007/s00769-004-0818-x