This article contains a list of commonly used medical abbreviations and acronyms that start with the letter A and may be encountered in medicine and radiology (please keep both the main list and any sublists in alphabetic order).

A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z - misc

• A

  • adenine (DNA nucleotide)

  • adenosine

  • alanine (single letter amino acid code)

  • ampere/amp (SI unit of current)

  • artery

  • blood type (ABO system)

  • vitamin A (retinol)

• A1-A5: annular pulleys

• AA

  • alcoholics anonymous

  • alleged assault

  • amino acid

  • amyloid A

  • anaplastic astrocytoma

  • aplastic anemia

  • arachidonic acid

• AAA

  • abdominal aortic aneurysm

  • achalasia-addisonianism-alacrima syndrome

  • acute anxiety attack

  • American Association of Anatomists

  • anti-actin antibodies

• AAC

  • adenocystic carcinoma

  • Advisory Appointment Committee (UK) 

• AACG: acute angle-closure glaucoma

• AAL: anterior axillary line

• AAOCA: anomalous aortic origin of coronary artery

• AARF: atlantoaxial rotatory fixation

• AAS

  • acute aortic syndrome

  • atlantoaxial subluxation

• AAST: American Association for the Surgery of Trauma

• AAU: acute anterior uveitis

• AB

  • abortion

  • antibiotics

  • antibody

  • blood type (ABO system)

• ABC

  • airway, breathing, circulation

  • aneurysmal bone cyst

  • antigen-binding capacity

  • atomic, biological, chemical (warfare)

• ABER: abduction and external rotation position

• ABG: arterial blood gas

• ABI

  • acquired brain injury

  • ankle-brachial index

• ABO: a blood type system

• ABPA: allergic bronchopulmonary aspergillosis

• ABPI: ankle-brachial pressure index

• ABR

  • American Board of Radiology

  • auditory brainstem response

• abs

  • absent

  • absolute

  • muscles of the abdomen

  • rectus abdominis muscle

• ABx: antibiotics

• AC

  • abdominal circumference

  • acromioclavicular (joint)

  • amniocentesis

  • anterior chamber

  • anterior commissure

  • anticoagulant

  • arachnoid cyst

  • ascending colon

  • axillary clearance

  • before meals (L: ante cibum)

• Ac: actinium

• ACA

  • anterior cerebral artery

  • anticardiolipin antibody

• ACDA: anterior cervical disc arthroplasty

• ACDF: anterior cervical discectomy and fusion

• ACE

  • acetylcholine esterase

  • Addenbrooke's Cognitive Examination

  • angiotensin-converting enzyme

• ACE-i: angiotensin-converting enzyme inhibitor

• ACGME: Accreditation Council for Graduate Medical Education

• ACh: acetylcholine

• AChE: acetylcholinesterase

• AChR: acetylcholine receptor

• ACJ: acromioclavicular joint

• ACL: anterior cruciate ligament

• ACLS: advanced cardiac life support

• ACOAS: anomalous origin of the coronary artery arising from the opposite sinus

• ACOM: anterior communicating artery

• AC-PC line: anterior commissure - posterior commissure line

• ACP: Amplatzer cardiac plug

• ACR: American College of Radiology

• ACS

  • abdominal compartment syndrome

  • acute coronary syndrome

  • altered conscious state

• ACTH: adrenocorticotropic hormone

• ACVS: acute COVID-19 vaccination syndrome

• AD

  • addict

  • alcohol dehydrogenase

  • Alzheimer disease

  • antidepressant

  • atopic dermatitis

  • autosomal dominant

  • axillary dissection

• ADC

  • apparent diffusion coefficient

  • analog-to-digital converter

• ADDS: adult deterioration detection system

• ADD-RS: aortic dissection detection risk score

• ADE: antibody-dependent enhancement

• ADEM: acute disseminating encephalomyelitis

• ADH: antidiuretic hormone

• ADHD: attention deficit hyperactivity disorder

• ADHF: acute decompensated heart failure

• ADI: atlantodental interval

• ADL: activities of daily living

• ADP: adenosine diphosphate

• ADR: adverse drug reaction

• ADRC: automatic dose rate control

• ADT: androgen deprivation therapy

• A&E: accident and emergency (department)

• A/E: accident and emergency (department)

• AE: air entry

• AEC: automatic exposure control

• AED: antiepileptic drug

• AEM: antiepileptic medication

• AF

  • amniotic fluid

  • atrial fibrillation

• AFB: acid-fast bacillus

• AFCU: accessory flexor carpi ulnaris muscle

• AFE: amniotic fluid embolism

• AFF: atypical femoral fracture

• AFH: angiomatoid fibrous histiocytoma

• AFI: amniotic fluid index

• AFL: air flow limitation

• AFP: alpha fetoprotein

• AFS: allergic fungal sinusitis

• AFUS: atypical follicular cells of undetermined significance

• A&G: advice and guidance

• AG

  • anion gap

  • antiglobulin (test)

• Ag

  • antigen

  • silver (Latin: argentum)

• AGUS: atypical glandular cells of undetermined significance

• A/G: albumin-globulin ratio

• AI

  • artificial insemination

  • artificial intelligence

  • assisted insemination

  • autoimmune

• AICA: anterior inferior cerebellar artery

• AICD: automated implantable cardiac defibrillator

• AIDS: acquired immunodeficiency syndrome

• AIHA: autoimmune hemolytic anemia

• AIIS: anterior inferior iliac spine

• AIN: acute interstitial nephritis

• AION: anterior ischemic optic neuropathy

• AIP: acute interstitial pneumonitis

• AIP: average intensity projection

• AIS: American Spinal Injury Association (ASIA) Impairment Scale

• AJL: anterior junctional line

• AJNR: American Journal of Neuroradiology

• AJR: American Journal of Roentgenology

• AKA

  • above knee amputation

  • also known as

• AKOA: accelerated knee osteoarthritis

• AKI: acute kidney injury

• AKU: alkaptonuria

• Al: aluminum

• Ala: alanine

• ALARA: as low as reasonably achievable

• ALARP: as low as reasonably practicable

• ALCAPA: anomalous left coronary artery from the pulmonary artery

• ALD

  • adrenoleukodystrophy

  • alcoholic liver disease

• ALHE: angiolymphoid hyperplasia with eosinophilia

• ALI

  • acute limb ischemia

  • acute lung injury

• ALIF: anterior lumbar interbody fusion

• ALK: anaplastic lymphoma kinase

• ALL

  • acute lymphoblastic leukemia

  • anterior longitudinal ligament

• ALND: axillary lymph node dissection

• ALOC: altered level of consciousness

• ALP: alkaline phosphatase

• ALPSA: anterior labroligamentous periosteal sleeve avulsion

• ALS

  • advanced life support

  • amyotrophic lateral sclerosis

• ALT

  • alanine transaminase

  • anterolateral thigh free flap

  • argon laser trabeculoplasty

  • atypical lipomatous tumor

• ALTE: acute life-threatening event

• ALVAL: aseptic lymphocyte-dominant vasculitis-associated lesion

• AM

  • abdominal migraine

  • acute marginal artery

• Am: americium

• AMA

  • advanced maternal age (obstetrics)

  • American Medical Association

  • antimitochondrial antibody

  • Australian Medical Association

• AMD: aged-related macular degeneration

• AmE: American English

• AMI

  • acute mitral insufficiency

  • acute myocardial infarct

• A-mode: amplitude mode (ultrasound)

• AML: acute myeloid leukemia

• AMP: adenosine monophosphate or adenylic acid 

• AMPA: α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid

• AMS: altered mental status

• AMV: anterior medullary vein

• AN

  • acoustic neuroma

  • aneurysm

  • anorexia nervosa

• ANA: antinuclear antibodies

• anat: anatomy

• ANC: acute necrotic collection

• ANCA: antineutrophil cytoplasmic antibody

• ANED: alive, no evidence of disease

• ANOCA: angina with open coronary arteries

• ANOH: anatomic neck of humerus

• Ao: aorta

• AOD: atlanto-occipital dissociation injury

• AOM: acute otomastoiditis

• AOS: aqueduct of Sylvius

• AOSD: adult-onset Still disease

• AP: anterior-posterior or anteroposterior

• APC: argon plasma coagulation

• APHE: arterial phase hyperenhancement

• APLA: antiphospholipid antibodies

• APLS: antiphospholipid syndrome

• APML: acute promyelocytic leukemia

• APMV: anterior pontomesencephalic vein

• APO: acute pulmonary edema

• APR: abdominoperineal resection

• APRV: airway pressure release ventilation

• APS

  • anterior perforated substance

  • antiphospholipid syndrome

• APSD: aortopulmonary septal defect

• APT: antiplatelet therapy

• APTT: activated partial thromboplastin time

• APUD: amine precursor uptake and decarboxylation

• APW: aortopulmonary window

• AR

  • anterior resection

  • aortic regurgitation

  • augmented reality

  • autosomal recessive

• Ar: argon

• ARBD: alcohol-related birth defects

• ARCAPA: anomalous right coronary artery from the pulmonary artery

• ARDS: acute respiratory distress syndrome

• ARF: acute renal failure

• Arg: arginine

• ARLD: alcohol-related liver disease

• ARND: alcohol-related neurodevelopmental disorders

• ARRS: American Roentgen Ray Society

• ARS: American Radium Society

• ART

  • antiretroviral therapy

  • assisted reproductive technology

• AS

  • active surveillance

  • ankylosing spondylitis

  • aortic sclerosis

  • aortic stenosis

  • associate specialist (UK)

• As: arsenic

• ASA: acetylsalicylic acid

• ASAD: arthroscopic subacromial decompression

• ASAP

  • as soon as possible

  • atypical small acinar proliferation

• ASB: anatomical snuff box

• ASBO: adhesive small bowel obstruction

• ASCVD: atherosclerotic cardiovascular disease

• ASD

  • atrial septal defect

  • autism spectrum disorder

• aSDH: acute subdural hemorrhage

• ASIA: American Spinal Injury Association

• ASIS: anterior superior iliac spine

• ASM: antiseizure medication

• Asn: asparagine

• ASNR: American Society of Neuroradiology

• ASP triad: anorectal malformation or congenital anorectal stenosis, sacrococcygeal osseous defect, presacral mass

• Asp: aspartic acid

• ASPECTS: Alberta stroke program early CT score

• ASR: atraumatic splenic rupture

• AST: aspartate transaminase

• ASUC: acute severe ulcerative colitis

• AT

  • antithrombin

  • atrial tachycardia

• At: astatine

• ATA: anterior tibial artery

• ATECO: auto-triggered elliptic centric-ordered (MRV)

• ATG: antithymocyte globulin

• ATFL: anterior talofibular ligament

• ATI: attenuation imaging

• ATL: anterior temporal lobectomy

• ATLS: advanced trauma life support

• ATOR: at time of review

• ATP: adenosine triphosphate

• ATRA: all-trans retinoic acid

• ATRT: atypical teratoid/rhabdoid tumor

• aTSR: anatomic total shoulder replacement

• ATTL: anterior tibiotalar ligament

• Au: gold (Latin: aurum)

• AUA: actual ultrasound age

• AUB: abnormal uterine bleeding

• AUR: acute urinary retention

• AUS: atypia of undetermined significance

• AV

  • aortic valve

  • atrioventricular

• AVB: abnormal vaginal bleeding

• AVF: arteriovenous fistula

• AVM: arteriovenous malformation

• AVN: avascular necrosis

• AVNRT: atrioventricular nodal re-entry tachycardia

• AVR

  • aortic valve repair

  • aortic valve replacement

• AVRT: atrioventricular re-entry tachycardia

• AVS: adrenal venous sampling

• AVSD: atrioventricular septal defect

• AWS: alcohol withdrawal scale

• Ax

  • axial

  • axilla

• AXR: abdominal x-ray

• AZ: apical zone

• AZT: azidothymidine (HIV drug) (a.k.a. zidovudine)