The Most Common Abbreviations Every Medical Coder Should Know

Medical coding is a language of its own—and much of that language is built on abbreviations. Whether you’re reviewing provider documentation, preparing for the CPC exam, or coding charts in a live production environment, abbreviations appear everywhere. Understanding them quickly and accurately is critical for correct code assignment, clean claim submission, and compliance.

Below is a streamlined guide to the most common abbreviations every medical coder should know, organized by category for easy study and real-world use.

Core Medical Coding Abbreviations

These are foundational abbreviations that appear across coding manuals, payer guidance, and workflow tools.

• CPT – Current Procedural Terminology

• ICD-10-CM – International Classification of Diseases, 10th Revision, Clinical Modification

• ICD-10-PCS – Procedure Coding System (inpatient hospital procedures)

• HCPCS – Healthcare Common Procedure Coding System

• CMS – Centers for Medicare & Medicaid Services

• NCCI – National Correct Coding Initiative

• E/M – Evaluation and Management

• RA – Remittance Advice

• CARC/RARC – Claim Adjustment Reason Code / Remittance Advice Remark Code

Healthcare & Clinical Documentation Abbreviations

Doctors often document using shorthand. Coders must know these to interpret the medical record correctly (and query when needed).

• Hx – History

• Dx – Diagnosis

• Tx – Treatment

• Rx – Prescription

• Sx – Symptoms

• CC – Chief Complaint

• HPI – History of Present Illness

• ROS – Review of Systems

• PE – Physical Exam

• VS – Vital Signs

• WNL – Within Normal Limits

• s/p – Status Post

• c/o – Complains Of

• PRN – As Needed

• NPO – Nothing by Mouth

Facility, Billing, and Insurance Abbreviations

Coders working with claims, Medicare, or facility-side billing will see these daily.

• DRG – Diagnosis-Related Group

• MS-DRG – Medicare Severity Diagnosis-Related Group

• OPPS – Outpatient Prospective Payment System

• IPPS – Inpatient Prospective Payment System

• HCC – Hierarchical Condition Category (risk adjustment)

• MA – Medicare Advantage

• POS – Place of Service

• TOB – Type of Bill

• DOS – Date of Service

• EOB – Explanation of Benefits

• TOS – Type of Service

Compliance & Quality Reporting Abbreviations

Coders must understand these to stay compliant with federal and payer rules.

• OIG – Office of Inspector General

• HIPAA – Health Insurance Portability and Accountability Act

• PHI – Protected Health Information

• MACRA – Medicare Access and CHIP Reauthorization Act

• MIPS – Merit-Based Incentive Payment System

• HEDIS – Healthcare Effectiveness Data and Information Set

• QI – Quality Improvement

Common Clinical Abbreviations by Body System

These appear frequently in provider documentation and can directly impact code selection.

Cardiovascular

• HTN – Hypertension

• CHF – Congestive Heart Failure

• CAD – Coronary Artery Disease

• MI – Myocardial Infarction

• AF or A-fib – Atrial Fibrillation

Respiratory

• COPD – Chronic Obstructive Pulmonary Disease

• SOB – Shortness of Breath

• URI – Upper Respiratory Infection

• ARDS – Acute Respiratory Distress Syndrome

Endocrine

• DM – Diabetes Mellitus

• DKA – Diabetic Ketoacidosis

• TSH – Thyroid-Stimulating Hormone

Neurology

• CVA – Cerebrovascular Accident (stroke)

• TIA – Transient Ischemic Attack

• LOC – Loss of Consciousness

Gastrointestinal

• GERD – Gastroesophageal Reflux Disease

• IBS – Irritable Bowel Syndrome

Procedure & Clinical Order Abbreviations

• ORIF – Open Reduction Internal Fixation

• CT – Computed Tomography

• MRI – Magnetic Resonance Imaging

• US – Ultrasound

• ECG/EKG – Electrocardiogram

• CABG – Coronary Artery Bypass Graft

• LFTs – Liver Function Tests

• BMP/CMP – Basic Metabolic Panel / Comprehensive Metabolic Panel

Abbreviations to Use With Caution

Some abbreviations are considered “dangerous” or ambiguous. Coders must query the provider if the meaning is unclear.

• U – “unit” (can look like 0 or 4)

• QD / QOD – daily / every other day

• MS / MSO₄ – can mean morphine or magnesium sulfate

Always follow facility policies and the Joint Commission “Do Not Use” abbreviation list.

Why Abbreviation Knowledge Matters

Understanding abbreviations isn’t just helpful—it’s essential for:

• Faster chart interpretation

• More accurate code assignment

• Stronger exam performance (CPC, CCS, etc.)

• Clean claims and fewer denials

• Better communication with providers and auditors

Coders who are fluent in medical terminology and abbreviations consistently have higher accuracy and stronger productivity.

Coding Clarified Blog 

Medline Plus Appendix B: Some Common Abbreviations 

Understanding Medical Words Tutorial from the National Library of Medicine