If the search division retrieves a compound when interrogating a database created by abstracting source documents (e.g. patents, journal articles or books) and deriving the chemical compounds disclosed in those documents and, on reading the source document, is unable to locate the compound, this does not automatically mean that an error has been made and that the compound is not disclosed in the document. For example, disclosed compounds which are named but whose structures are not drawn are still part of the disclosure and will be abstracted. In addition, database providers use standard nomenclature in their database records, whereas authors of technical literature frequently do not. Consequently, the nomenclature used for the compound in the database record may not be the same as that used in the source document.

However, in certain cases the search division is really unable to locate the compound in the source document, and this compound is relevant to the assessment of patentability. In such cases, the search division may write to the database provider asking why the compound in question was abstracted from that document and where it is disclosed in it. If the reply from the database provider is not available when the search report is drafted, the document is cited in the search report and used in the search opinion on the assumption that the compound is disclosed in the document. However, the search division does also continue the search as though the compound did not exist.