ICD-10-CM Official Guidelines
The FY 2027 ICD-10-CM Official Guidelines for Coding and Reporting (effective October 1, 2026 – September 30, 2027), searchable and linked section by section. Adherence to these guidelines is required under HIPAA.
Contents
- ICD-10-CM Official Guidelines for Coding and Reporting
- Section I. Conventions, general coding guidelines and chapter specific guidelines
- A. Conventions for the ICD-10-CM
- 1. The Alphabetic Index and Tabular List
- 2. Format and Structure:
- 3. Use of codes for reporting purposes
- 4. Placeholder character
- 5. 7th Characters
- 6. Abbreviations
- 7. Punctuation
- 8. Use of “and”.
- 9. Other and Unspecified codes
- 10. Includes Notes
- 11. Inclusion terms
- 12. Excludes Notes
- 13. Etiology/manifestation convention (“code first”, “use additional code” and “in diseases classified elsewhere” notes)
- 14. “And”
- 15. “With”
- 16. “See” and “See Also”
- 17. “Code also” note
- 18. Default codes
- 19. Code assignment and Clinical Criteria
- B. General Coding Guidelines
- 1. Locating a code in the ICD-10-CM
- 2. Level of Detail in Coding
- 3. Code or codes from A00.0 through T88.9, Z00-Z99.8, U00-U85
- 4. Signs and symptoms
- 5. Conditions that are an integral part of a disease process
- 6. Conditions that are not an integral part of a disease process
- 7. Multiple coding for a single condition
- 8. Acute and Chronic Conditions
- 9. Combination Code
- 10. Sequela (Late Effects)
- 11. Impending or Threatened Condition
- 12. Reporting Same Diagnosis Code More than Once
- 13. Laterality
- 14. Documentation by Clinicians Other than the Patient's Provider
- 15. Syndromes
- 16. Documentation of Complications of Care
- 17. Borderline Diagnosis
- 18. Use of Sign/Symptom/Unspecified Codes
- 19. Coding for Healthcare Encounters in Hurricane Aftermath
- 20. Multiple Sites Coding
- C. Chapter-Specific Coding Guidelines
- 1. Chapter 1: Certain Infectious and Parasitic Diseases (A00-B99), U07.1, U09.9
- a. Human Immunodeficiency Virus (HIV) Infections
- b. Infectious agents as the cause of diseases classified to other chapters
- c. Infections resistant to antibiotics
- d. Sepsis, Severe Sepsis, and Septic Shock
- e. Methicillin Resistant Staphylococcus aureus (MRSA) Conditions
- f. Zika virus infections
- g. Coronavirus infections
- 2. Chapter 2: Neoplasms (C00-D49)
- a. Admission/Encounter for treatment of primary site
- b. Admission/Encounter for treatment of secondary site
- c. Coding and sequencing of complications
- d. Primary malignancy previously excised
- e. Admissions/Encounters involving antineoplastic chemotherapy, immunotherapy and radiation therapy
- f. Admission/encounter to determine extent of malignancy
- g. Symptoms, signs, and abnormal findings listed in Chapter 18 associated with neoplasms
- h. Admission/encounter for pain control/management
- i. Malignancy in two or more noncontiguous sites
- j. Disseminated malignant neoplasm, unspecified
- k. Malignant neoplasm without specification of site
- l. Sequencing of neoplasm codes
- m. Current malignancy versus personal history of malignancy
- n. Leukemia, Multiple Myeloma, and Malignant Plasma Cell Neoplasms in remission versus personal history
- o. Aftercare following surgery for neoplasm
- p. Follow-up care for completed treatment of a malignancy
- q. Prophylactic organ removal for prevention of malignancy
- r. Malignant neoplasm associated with transplanted organ
- s. Breast Implant Associated Anaplastic Large Cell Lymphoma
- t. Secondary malignant neoplasm of lymphoid tissue
- 3. Chapter 3: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)
- 4. Chapter 4: Endocrine, Nutritional, and Metabolic Diseases (E00-E89)
- a. Diabetes mellitus
- b. Obesity
- 5. Chapter 5: Mental, Behavioral and Neurodevelopmental disorders (F01 – F99)
- a. Pain disorders related to psychological factors
- b. Mental and behavioral disorders due to psychoactive substance use
- c. Factitious Disorder
- 6. Chapter 6: Diseases of the Nervous System (G00-G99)
- a. Dominant/nondominant side
- b. Pain - Category G89
- 7. Chapter 7: Diseases of the Eye and Adnexa (H00-H59)
- a. Glaucoma
- b. Blindness
- 8. Chapter 8: Diseases of the Ear and Mastoid Process (H60-H95)
- 9. Chapter 9: Diseases of the Circulatory System (I00-I99)
- a. Hypertension
- b. Atherosclerotic Coronary Artery Disease and Angina
- c. Intraoperative and Postprocedural Cerebrovascular Accident
- d. Sequelae of Cerebrovascular Disease
- e. Acute myocardial infarction (AMI)
- 10. Chapter 10: Diseases of the Respiratory System (J00-J99), U07.0
- a. Chronic Obstructive Pulmonary Disease [COPD] and Asthma
- b. Acute Respiratory Failure
- c. Influenza due to certain identified influenza viruses
- d. Ventilator associated Pneumonia
- e. Vaping-related disorders
- 11. Chapter 11: Diseases of the Digestive System (K00-K95)
- 12. Chapter 12: Diseases of the Skin and Subcutaneous Tissue (L00-L99)
- a. Pressure ulcer stage codes
- b. Non-Pressure Chronic Ulcers
- 13. Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)
- a. Site and laterality
- b. Acute traumatic versus chronic or recurrent musculoskeletal conditions
- c. Coding of Pathologic Fractures
- d. Osteoporosis
- e. Multisystem Inflammatory Syndrome
- 14. Chapter 14: Diseases of Genitourinary System (N00-N99)
- a. Chronic kidney disease
- 15. Chapter 15: Pregnancy, Childbirth, and the Puerperium (O00-O9A)
- a. General Rules for Obstetric Cases
- b. Selection of OB Principal or First-listed Diagnosis
- c. Pre-existing conditions versus conditions due to the pregnancy
- d. Pre-existing hypertension in pregnancy
- e. Fetal Conditions Affecting the Management of the Mother
- f. HIV Infection in Pregnancy, Childbirth and the Puerperium
- g. Diabetes mellitus in pregnancy
- h. Long term use of insulin and oral hypoglycemics
- i. Gestational (pregnancy induced) diabetes
- j. Sepsis and septic shock complicating abortion, pregnancy, childbirth and the puerperium
- k. Puerperal sepsis
- l. Alcohol, tobacco and drug use during pregnancy, childbirth and the puerperium
- m. Poisoning, toxic effects, adverse effects and underdosing in a pregnant patient
- n. Normal Delivery, Code O80
- o. The Peripartum and Postpartum Periods
- p. Code O94, Sequelae of complication of pregnancy, childbirth, and the puerperium
- q. Termination of Pregnancy and Spontaneous abortions
- r. Abuse in a pregnant patient
- s. COVID-19 infection in pregnancy, childbirth, and the puerperium
- 16. Chapter 16: Certain Conditions Originating in the Perinatal Period (P00-P96)
- a. General Perinatal Rules
- b. Observation and Evaluation of Newborns for Suspected Conditions not Found
- c. Coding Additional Perinatal Diagnoses
- d. Prematurity and Fetal Growth Retardation
- e. Low birth weight and immaturity status
- f. Bacterial Sepsis of Newborn
- g. Stillbirth
- h. COVID-19 Infection in Newborn
- 17. Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA1)
- 18. Chapter 18: Symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
- a. Use of symptom codes
- b. Use of a symptom code with a definitive diagnosis code
- c. Combination codes that include symptoms
- d. Repeated falls
- e. Coma
- f. Functional quadriplegia
- g. SIRS due to Non-Infectious Process
- h. Death NOS
- i. NIHSS Stroke Scale
- 19. Chapter 19: Injury, poisoning, and certain other consequences of external causes (S00-T88)
- a. Application of 7th Characters in Chapter 19
- b. Coding of Injuries
- c. Coding of Traumatic Fractures
- d. Coding of Burns and Corrosions
- e. Adverse Effects, Poisoning, Underdosing and Toxic Effects
- f. Adult and child abuse, neglect and other maltreatment
- g. Complications of care
- 20. Chapter 20: External Causes of Morbidity (V00-Y99)
- a. General External Cause Coding Guidelines
- b. Place of Occurrence Guideline
- c. Activity Code
- d. Place of Occurrence, Activity, and Status Codes Used with other External Cause Code
- e. If the Reporting Format Limits the Number of External Cause Codes
- f. Multiple External Cause Coding Guidelines
- g. Child and Adult Abuse Guideline
- h. Unknown or Undetermined Intent Guideline
- i. Sequelae (Late Effects) of External Cause Guidelines
- j. Terrorism Guidelines
- k. External Cause Status
- 21. Chapter 21: Factors influencing health status and contact with health services (Z00-Z99)
- a. Use of Z Codes in Any Healthcare Setting
- b. Z Codes Indicate a Reason for an Encounter or Provide Additional Information about a Patient Encounter
- c. Categories of Z Codes
- 22. Chapter 22: Codes for Special Purposes (U00-U85)
- Section II. Selection of Principal Diagnosis
- A. Codes for symptoms, signs, and ill-defined conditions
- B. Two or more interrelated conditions, each potentially meeting the definition for principal diagnosis.
- C. Two or more diagnoses that equally meet the definition for principal diagnosis
- D. Two or more comparative or contrasting conditions
- E. A symptom(s) followed by contrasting/comparative diagnoses
- F. Original treatment plan not carried out
- G. Complications of surgery and other medical care
- H. Uncertain Diagnosis
- I. Admission from Observation Unit
- J. Admission from Outpatient Surgery
- K. Admissions/Encounters for Rehabilitation
- Section III. Reporting Additional Diagnoses
- A. Previous conditions
- B. Abnormal findings
- C. Uncertain Diagnosis
- Section IV. Diagnostic Coding and Reporting Guidelines for Outpatient Services
- A. Selection of first-listed condition
- B. Codes from A00.0 through T88.9, Z00-Z99, U00-U85
- C. Accurate reporting of ICD-10-CM diagnosis codes
- D. Codes that describe symptoms and signs
- E. Encounters for circumstances other than a disease or injury
- F. Level of Detail in Coding
- G. ICD-10-CM code for the diagnosis, condition, problem, or other reason for encounter/visit
- H. Uncertain diagnosis
- I. Chronic diseases
- J. Code all documented conditions that coexist
- K. Patients receiving diagnostic services only
- L. Patients receiving therapeutic services only
- M. Patients receiving preoperative evaluations only
- N. Ambulatory surgery
- O. Routine outpatient prenatal visits
- P. Encounters for general medical examinations with abnormal findings
- Q. Encounters for routine health screenings
- Appendix I: Present on Admission Reporting Guidelines
ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and NCHS (public domain) and approved by the Cooperating Parties (AHA, AHIMA, CMS, NCHS). Always consult the official PDF for the authoritative text.