The CNA as National Reference Laboratory (NRL) collaborates with the following European Union Reference Laboratories (EURL):

• ANSES (Fougères. France)
• RIKILT (Wageningen. Netherlands)
• BVL (Berlin. Germany)

attending the meetings held by these laboratories and participating in the intercomparison tests that they organise periodically.

The CNA is accredited in accordance with Standard UNE-EN-ISO/IEC 17025 and Technical Note 18 of ENAC (flexible scope) for the analysis of residues of veterinary drugs and related substances in foods, as well as for products of animal origin, by liquid chromatography in groups for which it is the NRL.

The analysis methods that the CNA currently has accredited, and therefore which are included in its List of Tests Under Accreditation (LEBA), correspond to the following groups of residues for which it was appointed in the scope of the National Residue Investigation Plan, PNIR (RD 1749/1998, Directive 96/23/EC):

• A1 (stilbenes)
• A3 (steroids)
• A4 (resorcylic acid lactones)
• A5 (beta-agonists)
• A6 (chloramphenicol, nitrofurans and dapsone)
• B1 (antimicrobials)
• B2f (corticosteroids) and
• B3e (dyes)

These methods are mainly based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS).

The CNA, as NRL since 1996 for the PNIR, has been carrying out an active role in this field with the functions that correspond to it as National Reference Laboratory.