ABN stands for Advanced Beneficiary Notification. An ABN must be signed prior to providing a Medicare service or test to document that the patient is willing to assume responsibility for payment of services that Medicare may not cover when subject to either National or Local Coverage Determinations (NCD) or (LCD).
Chinchillas are crepuscular (most active around dawn and dusk) rodents, slightly larger and more robust than ground squirrels. They are native to the Andes mountains in South America and live in colonies called  herds  at high elevations up to 4,270 m (14,000 ft).
The head is broad and the external ears are large. Chinchillas have large, black eyes with a vertical split pupil, vestigial cheek pouches, and incisors with colored enamel. Both the forefoot and hindfoot have four digits with stiff bristles surrounding the weak claws. (Nowak 1991, Grzimek 1975)