INTRODUCTION

This chapter provides an approach for determining an appropriate numeric value for the reporting threshold (see Impurities in Drug Substances and Drug Products 〈1086〉, Glossary) in chromatographic test procedures and is applicable when the chapter is referenced in an individual monograph employing a user-determined reporting threshold. Monographs that employ user-determined reporting thresholds offer flexibility, ensuring the documentary standard is fit for its intended purpose, by permitting users to determine the reporting threshold criterion that aligns with their product-specific implementation of the compendial chromatographic test procedure. USP may specify user-determined reporting thresholds in monographs for chemically derived drug substances and drug products. User-determined reporting thresholds are generally not applicable in monographs for veterinary only products, biological/biotechnological products, peptides, oligonucleotides, radiopharmaceuticals, fermentation products, and semi-synthetic products derived therefrom, herbal products, and crude products of animal or plant origin. Monographs that specify user-determined reporting thresholds will typically provide a note as supplemental information that is not essential for regulatory compliance, to aid users who are not product application holders in identifying a numeric value for the reporting threshold that may be suitable for a given set of product-specific factors.