1. If a USP or NF monograph includes an assay or organic impurity test based on chromatography, other than a test for residual solvents, and that monograph procedure does not detect an impurity present in the substance, the amount and identity of the impurity, where both are known, shall be stated in the labeling (certificate of analysis) of the official substance, under the heading Other Impurity(ies).
2. The presence of any unlabeled other impurity in an official substance is a variance from the standard if the content is 0.1% or greater. The sum of all Other Impurities combined with the monograph-detected impurities may not exceed 2.0%(see Ordinary Impurities <466>), unless otherwise stated in the monograph.