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RegisterDifference in values between reanalysed and ISR samples [Bioanalytics]
Dear ohlbe,
Pl read my response in blue
Each subject(three period) was analysed against a calibration curve and similarly for the repeat subjects
Yes, it was either -25 to -30% or + 25-30%
The difference was consistently on higher for two repeat subjects and lower for the other. ISR was performed at the end of the study.
Pl read my response in blue
❝ - in how many runs were the samples of these 3 subjects analysed initially ? How many runs for re-analysis ?
Each subject(three period) was analysed against a calibration curve and similarly for the repeat subjects
❝ - was the difference always in the same direction for all samples for each subject ? If yes, it just looks like an accuracy issue (one run may be 15 % too high, the second 15 % too low).
Yes, it was either -25 to -30% or + 25-30%
❝ - was the difference in the same direction for the 3 subjects ? Higher, or lower than the initial result ? If the difference was systematically in the same direction, with 3 independent runs, you may have an issue with stability (either of the parent analyte, or of a metabolite). Did you analyse your ISR runs only at the end of the study, or on an ongoing basis each time you had enough samples to re-analyse in a run ?
The difference was consistently on higher for two repeat subjects and lower for the other. ISR was performed at the end of the study.
Complete thread:
- Difference in values between reanalysed and ISR samples cakhatri 2013-03-10 09:41
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Difference in values between reanalysed and ISR samples Ohlbe 2013-03-11 18:58
- Difference in values between reanalysed and ISR samplescakhatri 2013-03-12 05:24
- Difference in values between reanalysed and ISR samples Ken Peh 2013-03-16 14:40
- Difference in values between reanalysed and ISR samples Ohlbe 2013-03-11 18:58
Ing. Helmut Schütz