(en) To the Editor, According to the ISO Guide 30, stability is defined as the “ability of a sample to maintain the initially measured value, within specified limits, of a constituent over a period of time under specified storage conditions. The instability is given as an absolute difference, as a quotient or as a percentage deviation of results obtained from measurements at initial time (T0) and after a given period of time (Tx)” [...]
Bastin, P., Favresse, J., Streel, C., Maisin, D., Fillee, C., & Gruson, D. (2018). Assessment of in vitro stability: a call for harmonization across studies. Clinical Chemistry and Laboratory Medicine : Associated with FESCC and IFCC, 56(5), e121-e124. https://doi.org/10.1515/cclm-2017-1024 (Original work published 2018)