The USDA classifies pain into four categories (B, C, D, and E). Protocols and annual reports must classify animals into a category and provide information on the number of animals being used and details on the types of procedures being performed. If any procedures fall into USDA’s Category D or E, causing more than momentary or slight pain or distress to the animals, the investigator must describe his/her consideration of alternatives (see the Searching the Literature tab) and the determination that alternatives are not available.
This category includes routine procedures which produce only momentary pain.
Animals are expected to experience pain or distress for which appropriate anesthetic, analgesic or tranquilizing drugs will be used to alleviate.
Surgical procedures (for which pain relief was provided) such as:
Blood collection by more invasive routes such as intracardiac or periorbital (in species without a true orbital sinus such as rats and guinea pigs) where pain and distress was relieved.
Administration of drugs, chemicals, toxins, or organisms that would be expected to produce pain or distress but which will be alleviated by analgesics
Prolonged restraint of an anima during which the distress will be mitigated by positive human contact and enrichment
Animals are expected to experience pain or distress for which the use of appropriate drugs would adversely affect the procedures, results, or interpretation of the research.