The EURL Berlin groups veterinary drug residues into minimum required, recommended, optional, and other residues, taking into account factors such as production and prescription volumes, suspected illicit application and frequency of residue detection in official control samples. Likewise, matrices for each compound class are grouped using the same rationale. Based on this classification the EURL Berlin evaluates the Member States’ National Residue Control Plans (NRCP) to highlight adequate aspects or point out areas where improvements might be required. In order to further promote the analysis of the most relevant residues and thereby harmonise residue analysis within its network, the EURL Berlin includes all minimum required and recommended residues in the proficiency assessment of its proficiency tests. The EURL Berlin regularly assess the adequacy of the classification taking into account new developments and substances may therefore be reassigned to a different priority group.

The classifications for substances of group B and the corresponding matrices according to Council Directive 96/23/EC Annex I are displayed below. If certain analytes are only relevant for specific matrices, the matrices are indicated in parentheses following the analyte. If only a parent compound is given, the information also applies to the respective relevant marker substances. The complete list including substances of group A according to Council Directive 96/23/EC Annex I can be retrieved from the FIS-VL.

Residue classification

group	analytes			
	minimum required	recommended	optional	other
B2a	abamectin (aquaculture muscle/ skin, egg) closantel (milk) doramectin (aquaculture muscle/ skin) fenbendazole (especially egg) ivermectin (aquaculture muscle/ skin, egg) levamisole (especially in egg) albendazole moxidectin (aquaculture muscle/ skin) nitroxinil (milk) rafoxanide (milk) thiabendazole triclabendazole	clorsulon emamectin (aquaculture muscle/ skin) eprinomectin (aquaculture muscle/ skin) flubenazole (especially in egg) mebendazole (especially in egg) oxibendazole oxyclozanide	cambendazole parbendazole praziquantel	afoxalaner cyclobendazole derquantel dicyclanil fluralaner haloxon lotilaner luxbendazole milbemectin A3, A4 monepantel morantel nemadectin niclosamid oxantel pamoate piperazine pyrantel salantel sarolaner selamectin sisapronil
B2b	diclazuril (egg) lasalocid (egg, poultry tissue) maduramicin (egg, poultry tissue) monensin (egg, poultry tissue) narasin (egg, poultry tissue) nicarbazin (egg) robenidine (egg, poultry tissue) salinomycin (egg, poultry tissue)	amprolium clopidol decoquinate halofuginone ipronidazole nequinate (methylbenzoquate) semduramycin toltrazuril	arprinocid carnidazole clazuril diaveridine dintolmide nitromide ornidazole secnidazole ternidazole tinidazole	2-[3,5-Dichloro-4-[(4-chlorophenyl)methyl]phenyl]- 1,2,4-triazine-3,5(2H,4H)-dione 3-Amino-2-methyl-5-nitrobenzamide avilmycin buquinolate dichloro isoevernic acid ethopabat imidocarb ionomycin nigericin nimorazole simeton toltrazuril sulfoxide
B2e	4- methylamino antipyrine carprofen diclofenac flunixin, flunixin-hydroxide (milk) ibuprofen meloxicam naproxen phenylbutazone tolfenamic acid	4-formylamino antipyrine flufenamic acid ketoprofen mefenamic acid niflumic acid oxyphenbutazone vedaprofen	antipyrine firocoxib isopyrine salicylic acid	4-acetamido antipyrine acetanilide aclofenac aminopropylone amyprone antipyrine azapropazone celecoxib dipyrone etodolac etoricoxib fenbufen flurbiprofen indomethacin indoprofen isoxicam ketorolac nabumetone nimeslide paracetamol parecoxib phenacetin piroxicam propyphenazon rofeocoxib sulindac tenoxicam tolmetin valdecoxib

Matrix classification

group	matrices
	absolute minimum requirements	recommended	optional
B2a		bovine liver or muscle bovine milk porcine liver or muscle ovine milk ovine liver or muscle caprine milk caprine liver or muscle liver or muscle of farmed game egg	equine liver or muscle liver or muscle of wild game
B2b	egg poultry tissue	bovine liver or muscle porcine liver or muscle ovine liver or muscle caprine liver or muscle rabbit liver or muscle feed	equine liver or muscle liver or muscle of farmed game
B2e		bovine matrices with special regard to milk equine matrices caprine matrices ovine matrices porcine matrices poultry matrices	matrices of farmed game rabbit matrices