European Bioanalysis Forum: recommendation for dealing with internal standard variability

Adequate monitoring of internal standard (IS) response across an analytical run and identification of anomalies is now a common expectation. However, the means to conduct this assessment in an appropriate manner is unclear and differs widely between laboratories. A European Bioanalysis Forum (EBF) topic team was formed to survey current practices within European Bioanalysis Forum member companies and to recommend a best practice approach for dealing with IS response variability. The inclusion of an IS within a bioanalytical assay is a fundamental concept that is often taken for granted. While many strive to use a stable isotope-labeled IS, it is...