| AT-P | antitrypsin-Pittsburgh |
|---|---|
| AT-PAS | aldehyde-thionine-periodic acid Schiff [test] |
| AT/GC | adenine-thymine/guanine-cytosine [ratio] |
| AT10 | dihydrotachysterol |
| ATA | alimentary toxic aleukia; American Thyroid Association; aminotriazole; antithymic activity; antithyroglobulin antibody; anti-Toxoplasma antibody; atmosphere absolute; aurintricarboxylic acid |
| ATB | at the time of the bomb [A-bomb in Japan]; atrial tachycardia with block |
| Atb | antibiotic |
| ATC | activated thymus cell; around the clock |
| ATCase | aspartate transcarbomoylase |
| ATCC | American Type Culture Collection |