This document gives guidelines on the handling, documentation, storage and processing of fine needle aspirates (FNAs) intended for protein examination during the pre-examination phase before a molecular examination is performed. This document is applicable to molecular in vitro diagnostic examinations including laboratory developed tests performed by medical laboratories and molecular pathology laboratories that examine proteins isolated from FNAs. It is also intended to be used by laboratory customers, in vitro diagnostics developers and manufacturers, biobanks, institutions and commercial organisations performing biomedical research, and regulatory authorities. Different dedicated measures are taken for collecting, stabilizing, transporting and storing of core needle biopsies (FNA Biopsy or FNA B) and are not covered in this document, but in EN ISO 20184-2, Molecular in vitro diagnostic examinations Specifications for pre-examination processes for frozen tissue Part 2: Isolated proteins and EN ISO 20166-2, Molecular in vitro diagnostic examinations Specifications for pre-examination processes for formalin fixed and paraffin-embedded (FFPE) tissue Part 2: Isolated proteins. This document is not applicable for protein examination by immunohistochemistry. NOTE International, national or regional regulations or requirements can also apply to specific topics covered in this document.