Medical abbreviations and acronyms (A)

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
  • alleged assault
  • alcoholics anonymous
  • amino acid
  • amyloid A
  • anaplastic astrocytoma
  • aplastic anaemia
  • 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
  • angiotensin-converting enzyme
• ACE-i: angiotensin-converting enzyme inhibitor
• ACGME: Accreditation Council for Graduate Medical Education
• ACh: acetylcholine
• AChE: acetylcholinesterase
• 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
• AD
  • addict
  • alcohol dehydrogenase
  • Alzheimer disease
  • antidepressant
  • atopic dermatitis
  • autosomal dominant
  • axillary dissection
• ADC
  • apparent diffusion coefficient
  • analogue-to-digital converter
• ADD-RS: aortic dissection detection risk score
• 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
• A&E: accident and emergency (department)
• A/E: accident and emergency (department)
• AE: air entry
• AF
  • amniotic fluid
  • atrial fibrillation
• AFB: acid-fast bacillus
• AFE: amniotic fluid embolism
• AFF: atypical femoral fracture
• AFI: amniotic fluid index
• AFP: alpha fetoprotein
• AFS: allergic fungal sinusitis
• AG
  • anion gap
  • antiglobulin (test)
• Ag
  • silver (Latin: argentum)
  • antigen
• A/G: albumin-globulin ratio
• AI
  • artificial insemination
  • assisted insemination
  • artificial intelligence
  • autoimmune
• AICA: anterior inferior cerebellar artery
• AICD: automated implantable cardiac defibrillator
• AIDS: acquired immunodeficiency syndrome
• AIHA: autoimmune haemolytic anaemia
• AIIS: anterior inferior iliac spine
• AIN: acute interstitial nephritis
• AION: anterior ischemic optic neuropathy
• AIP: acute interstitial pneumonitis
• AIP: average intensity projection
• AJL: anterior junctional line
• AJNR: American Journal of Neuroradiology
• AJR: American Journal of Roentgenology
• AKA: above knee amputation
• AKOA: accelerated knee osteoarthritis
• AKI: acute kidney injury
• AKU: alkaptonuria
• Al: aluminium
• 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 ischaemia
  • acute lung injury
• ALIF: anterior lumbar interbody fusion
• ALL
  • acute lymphoblastic leukaemia
  • anterior longitudinal ligament
• ALND: axillary lymph node dissection
• ALOC: altered level of consciousness
• ALP: alkaline phosphatase
• ALPSA: anterior labroligamentous periosteal sleeve avulsion
• ALS
  • amyotrophic lateral sclerosis
  • advanced life support
• ALT
  • alanine transaminase
  • anterolateral thigh free flap
  • argon laser trabeculoplasty
  • atypical lipomatous tumour
• ALTE: acute life-threatening event
• ALVAL: aseptic lymphocyte-dominant vasculitis-associated lesion
• AM
  • abdominal migraine
  • acute marginal artery
• Am: americium
• AMA:
  • American Medical Association
  • Australian Medical Association
  • advanced maternal age (obstetrics)
• AmE: American English
• AMI
  • acute myocardial infarct
  • acute mitral insufficiency
• A-mode: amplitude mode (ultrasound)
• AMP: adenosine monophosphate or adenylic acid 
• AMPA: α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid
• AMS: altered mental status
• AN
  • acoustic neuroma
  • anorexia nervosa
  • aneurysm
• ANA: antinuclear antibodies
• anat: anatomy
• ANED: alive, no evidence of disease
• ANOH: anatomic neck of humerus
• Ao: aorta
• AOD: atlanto-occipital dissociation injury
• AOM: acute otomastoiditis
• AP: anterior-posterior or anteroposterior
• APLA: antiphospholipid antibodies
• APLS: antiphospholipid syndrome
• APML: acute promyelocytic leukaemia
• APO: acute pulmonary oedema
• APR: abdominoperineal resection
• APRV: airway pressure release ventilation
• APS
  • anterior perforated substance
  • antiphospholipid syndrome
• APT: antiplatelet therapy
• APTT: activated partial thromboplastin time
• APUD: amine precursor uptake and decarboxylation
• APW: aortopulmonary window
• AR
  • aortic regurgitation
  • augmented reality
  • autosomal recessive
• Ar: argon
• ARDS: acute respiratory distress syndrome
• ARF: acute renal failure
• Arg: arginine
• ARRS: American Roentgen Ray Society
• ARS: American Radium Society
• ART: assisted reproductive technology
• AS
  • active surveillance
  • ankylosing spondylitis
  • aortic sclerosis
  • aortic stenosis
  • associate specialist (UK)
• As: arsenic
• ASA: acetylsalicylic acid
• ASAP
  • as soon as possible
  • atypical small acinar proliferation
• ASB: anatomical snuff box
• ASD
  • atrial septal defect
  • autistic spectrum disorder
• aSDH: acute subdural haemorrhage
• ASIS: anterior superior iliac spine
• 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: atrial tachycardia
• At: astatine
• ATA: anterior tibial artery
• ATECO: auto-triggered elliptic centric-ordered (MRV)
• ATG: antithymocyte globulin
• ATFL: anterior talofibular ligament
• 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 tumour
• Au: gold (Latin: aurum)
• AUB: abnormal uterine bleeding
• AUR: acute urinary retention
• AV
  • aortic valve
  • atrioventricular
• AVF: arteriovenous fistula
• AVM: arteriovenous malformation
• AVNRT: AV nodal re-entry tachycardia
• AVR: aortic valve replacement
• AVSD: atrioventricular septal defect
• Ax
  • axial
  • axilla
• AXR: abdominal X-ray
• AZ: apical zone
• AZT: azidothymidine (HIV drug) (a.k.a. zidovudine)