| CU | cardiac unit; casein unit; cause unknown or undetermined; chymotrypsin unit; clinical unit; color un... |
|---|---|
| CUD | cause undetermined; congenital urinary deformity |
| UCOD | underlying cause of death |
| IAR | immediate asthma reaction; inhibitory anal reflex; iodine-azide reaction |
| IDLH | immediate danger to life and health |