# ICD-10 Coding Pro — Full Reference > Complete ICD-10-CM diagnosis code reference with 70,000+ codes, official > descriptions, billability status, and clinical coding guidelines. > Updated for 2024–2026 editions. > > Website: https://icd10codingpro.com > Code lookup: https://icd10codingpro.com/codes/{CODE} > Search: https://icd10codingpro.com/?q={query} --- ## How ICD-10-CM Codes Work ICD-10-CM (International Classification of Diseases, 10th Revision, Clinical Modification) is the US standard for reporting diagnoses in healthcare settings. **Code structure:** - 3–7 characters long: 1 letter + 2 digits + optional decimal + up to 4 more characters - First character (A–Z) indicates the chapter/body system - Characters 4–7 add clinical detail (site, laterality, severity, encounter type) - A code is **billable** only at its most specific level (leaf node) - Non-billable codes are category headers that require additional characters **Example: E11 (Type 2 diabetes mellitus)** - E11 — Category (non-billable, needs more digits) - E11.9 — Unspecified (billable) - E11.65 — With hyperglycemia (billable) - E11.21 — With diabetic nephropathy (billable) **7th character extensions** (Chapters 19–20): - A = initial encounter - D = subsequent encounter - S = sequela (late effect) **Billability rule:** Always code to the highest level of specificity supported by the clinical documentation. A 3-character code is billable only when no 4–7 character codes exist beneath it. --- ## Most Common Diagnosis Codes ### Infectious & Parasitic Diseases (Chapter 1: A00–B99) - A09 — Infectious gastroenteritis and colitis, unspecified (Billable) - A41.9 — Sepsis, unspecified organism (Billable) - A41.01 — Sepsis due to Methicillin susceptible Staphylococcus aureus (Billable) - A41.02 — Sepsis due to Methicillin resistant Staphylococcus aureus (Billable) - A49.02 — Methicillin resistant Staphylococcus aureus infection, unspecified site (Billable) - B34.9 — Viral infection, unspecified (Billable) - B37.0 — Candidal stomatitis (Billable) - B95.61 — MSSA as the cause of diseases classified elsewhere (Billable) - B95.62 — MRSA as the cause of diseases classified elsewhere (Billable) - B97.29 — Other coronavirus as the cause of diseases classified elsewhere (Billable) ### Neoplasms (Chapter 2: C00–D49) - C18.9 — Malignant neoplasm of colon, unspecified (Billable) - C34.90 — Malignant neoplasm of unspecified part of unspecified bronchus or lung (Billable) - C50.919 — Malignant neoplasm of unspecified site of unspecified female breast (Billable) - C61 — Malignant neoplasm of prostate (Billable) - C64.9 — Malignant neoplasm of unspecified kidney, except renal pelvis (Billable) - D49.0 — Neoplasm of unspecified behavior of digestive system (Billable) - D64.9 — Anemia, unspecified (Billable) ### Blood & Immune Disorders (Chapter 3: D50–D89) - D50.9 — Iron deficiency anemia, unspecified (Billable) - D62 — Acute posthemorrhagic anemia (Billable) - D69.6 — Thrombocytopenia, unspecified (Billable) - D72.829 — Elevated white blood cell count, unspecified (Billable) ### Endocrine, Nutritional & Metabolic Diseases (Chapter 4: E00–E89) - E03.9 — Hypothyroidism, unspecified (Billable) - E05.90 — Thyrotoxicosis, unspecified without thyrotoxic crisis or storm (Billable) - E07.9 — Disorder of thyroid, unspecified (Billable) - E10.9 — Type 1 diabetes mellitus without complications (Billable) - E10.10 — Type 1 diabetes mellitus with ketoacidosis without coma (Billable) - E10.65 — Type 1 diabetes mellitus with hyperglycemia (Billable) - E11.9 — Type 2 diabetes mellitus without complications (Billable) - E11.21 — Type 2 diabetes mellitus with diabetic nephropathy (Billable) - E11.22 — Type 2 diabetes mellitus with diabetic chronic kidney disease (Billable) - E11.40 — Type 2 diabetes mellitus with diabetic neuropathy, unspecified (Billable) - E11.65 — Type 2 diabetes mellitus with hyperglycemia (Billable) - E11.69 — Type 2 diabetes mellitus with other specified complication (Billable) - E13.9 — Other specified diabetes mellitus without complications (Billable) - E66.01 — Morbid (severe) obesity due to excess calories (Billable) - E66.09 — Other obesity due to excess calories (Billable) - E78.00 — Pure hypercholesterolemia, unspecified (Billable) - E78.1 — Pure hyperglyceridemia (Billable) - E78.5 — Hyperlipidemia, unspecified (Billable) - E83.42 — Hypomagnesemia (Billable) - E86.0 — Dehydration (Billable) - E87.1 — Hypo-osmolality and hyponatremia (Billable) - E87.5 — Hyperkalemia (Billable) - E87.6 — Hypokalemia (Billable) ### Mental & Behavioral Disorders (Chapter 5: F01–F99) - F10.20 — Alcohol dependence, uncomplicated (Billable) - F10.239 — Alcohol dependence with withdrawal, unspecified (Billable) - F11.20 — Opioid dependence, uncomplicated (Billable) - F17.210 — Nicotine dependence, cigarettes, uncomplicated (Billable) - F20.9 — Schizophrenia, unspecified (Billable) - F31.9 — Bipolar disorder, unspecified (Billable) - F32.0 — Major depressive disorder, single episode, mild (Billable) - F32.1 — Major depressive disorder, single episode, moderate (Billable) - F32.9 — Major depressive disorder, single episode, unspecified (Billable) - F33.0 — Major depressive disorder, recurrent, mild (Billable) - F33.1 — Major depressive disorder, recurrent, moderate (Billable) - F41.0 — Panic disorder without agoraphobia (Billable) - F41.1 — Generalized anxiety disorder (Billable) - F41.9 — Anxiety disorder, unspecified (Billable) - F43.10 — Post-traumatic stress disorder, unspecified (Billable) ### Nervous System (Chapter 6: G00–G99) - G20 — Parkinson's disease (Billable) - G30.9 — Alzheimer's disease, unspecified (Billable) - G40.909 — Epilepsy, unspecified, not intractable, without status epilepticus (Billable) - G43.909 — Migraine, unspecified, not intractable, without status migrainosus (Billable) - G47.00 — Insomnia, unspecified (Billable) - G47.33 — Obstructive sleep apnea (Billable) - G89.29 — Other chronic pain (Billable) ### Eye & Adnexa (Chapter 7: H00–H59) - H25.9 — Unspecified age-related cataract (Billable) - H35.30 — Unspecified macular degeneration (Billable) - H40.10X0 — Unspecified open-angle glaucoma, stage unspecified (Billable) ### Ear & Mastoid (Chapter 8: H60–H95) - H61.20 — Impacted cerumen, unspecified ear (Billable) - H91.90 — Unspecified hearing loss, unspecified ear (Billable) ### Circulatory System (Chapter 9: I00–I99) - I10 — Essential (primary) hypertension (Billable) - I11.0 — Hypertensive heart disease with heart failure (Billable) - I11.9 — Hypertensive heart disease without heart failure (Billable) - I13.10 — Hypertensive heart and chronic kidney disease without heart failure, with CKD stage 1–4 (Billable) - I20.0 — Unstable angina (Billable) - I21.4 — Acute subendocardial myocardial infarction (Billable) - I25.10 — Atherosclerotic heart disease of native coronary artery without angina pectoris (Billable) - I25.110 — Atherosclerotic heart disease of native coronary artery with unstable angina pectoris (Billable) - I25.5 — Ischemic cardiomyopathy (Billable) - I25.9 — Chronic ischemic heart disease, unspecified (Billable) - I48.0 — Paroxysmal atrial fibrillation (Billable) - I48.2 — Chronic atrial fibrillation (Billable) - I48.91 — Unspecified atrial fibrillation (Billable) - I50.9 — Heart failure, unspecified (Billable) - I50.20 — Unspecified systolic (congestive) heart failure (Billable) - I50.22 — Chronic systolic (congestive) heart failure (Billable) - I50.30 — Unspecified diastolic (congestive) heart failure (Billable) - I50.32 — Chronic diastolic (congestive) heart failure (Billable) - I63.9 — Cerebral infarction, unspecified (Billable) - I65.29 — Occlusion and stenosis of unspecified carotid artery (Billable) - I69.30 — Unspecified sequelae of cerebral infarction (Billable) - I70.0 — Atherosclerosis of aorta (Billable) - I73.9 — Peripheral vascular disease, unspecified (Billable) ### Respiratory System (Chapter 10: J00–J99) - J06.9 — Acute upper respiratory infection, unspecified (Billable) - J18.9 — Pneumonia, unspecified organism (Billable) - J20.9 — Acute bronchitis, unspecified (Billable) - J44.0 — COPD with acute lower respiratory infection (Billable) - J44.1 — COPD with acute exacerbation (Billable) - J44.9 — COPD, unspecified (Billable) - J45.20 — Mild intermittent asthma, uncomplicated (Billable) - J45.50 — Severe persistent asthma, uncomplicated (Billable) - J45.909 — Unspecified asthma, uncomplicated (Billable) - J96.00 — Acute respiratory failure, unspecified whether with hypoxia or hypercapnia (Billable) - J96.01 — Acute respiratory failure with hypoxia (Billable) ### Digestive System (Chapter 11: K00–K95) - K21.0 — Gastro-esophageal reflux disease with esophagitis (Billable) - K25.9 — Gastric ulcer, unspecified, without hemorrhage or perforation (Billable) - K35.80 — Unspecified acute appendicitis (Billable) - K40.90 — Unilateral inguinal hernia, without obstruction or gangrene, not recurrent (Billable) - K50.90 — Crohn's disease, unspecified, without complications (Billable) - K51.90 — Ulcerative colitis, unspecified, without complications (Billable) - K57.30 — Diverticulosis of large intestine without perforation or abscess without bleeding (Billable) - K70.30 — Alcoholic cirrhosis of liver without ascites (Billable) - K76.0 — Fatty (change of) liver, not elsewhere classified (Billable) - K80.20 — Calculus of gallbladder without cholecystitis without obstruction (Billable) - K92.1 — Melena (Billable) ### Skin & Subcutaneous Tissue (Chapter 12: L00–L99) - L03.90 — Cellulitis, unspecified (Billable) - L40.0 — Psoriasis vulgaris (Billable) - L89.90 — Pressure ulcer of unspecified site, unspecified stage (Billable) - L97.509 — Non-pressure chronic ulcer of other part of unspecified foot with unspecified severity (Billable) ### Musculoskeletal System (Chapter 13: M00–M99) - M17.11 — Primary osteoarthritis, right knee (Billable) - M17.12 — Primary osteoarthritis, left knee (Billable) - M19.90 — Unspecified osteoarthritis, unspecified site (Billable) - M25.561 — Pain in right knee (Billable) - M25.562 — Pain in left knee (Billable) - M54.2 — Cervicalgia (Billable) - M54.5 — Low back pain (Billable) - M54.6 — Pain in thoracic spine (Billable) - M62.82 — Rhabdomyolysis (Billable) - M79.3 — Panniculitis, unspecified (Billable) - M81.0 — Age-related osteoporosis without current pathological fracture (Billable) ### Genitourinary System (Chapter 14: N00–N99) - N17.9 — Acute kidney failure, unspecified (Billable) - N18.1 — Chronic kidney disease, stage 1 (Billable) - N18.2 — Chronic kidney disease, stage 2 (mild) (Billable) - N18.3 — Chronic kidney disease, stage 3 (moderate) (Billable) - N18.4 — Chronic kidney disease, stage 4 (severe) (Billable) - N18.5 — Chronic kidney disease, stage 5 (Billable) - N18.6 — End stage renal disease (Billable) - N18.9 — Chronic kidney disease, unspecified (Billable) - N39.0 — Urinary tract infection, site not specified (Billable) - N40.0 — Benign prostatic hyperplasia without lower urinary tract symptoms (Billable) ### Pregnancy, Childbirth & Puerperium (Chapter 15: O00–O9A) - O24.410 — Gestational diabetes mellitus in pregnancy, diet controlled (Billable) - O24.414 — Gestational diabetes mellitus in pregnancy, insulin controlled (Billable) - O99.810 — Abnormal glucose complicating pregnancy (Billable) ### Symptoms & Abnormal Findings (Chapter 18: R00–R99) - R00.0 — Tachycardia, unspecified (Billable) - R05.9 — Cough, unspecified (Billable) - R06.00 — Dyspnea, unspecified (Billable) - R06.02 — Shortness of breath (Billable) - R07.9 — Chest pain, unspecified (Billable) - R10.9 — Unspecified abdominal pain (Billable) - R10.84 — Generalized abdominal pain (Billable) - R11.0 — Nausea (Billable) - R11.10 — Vomiting, unspecified (Billable) - R19.7 — Diarrhea, unspecified (Billable) - R42 — Dizziness and giddiness (Billable) - R50.9 — Fever, unspecified (Billable) - R51.9 — Headache, unspecified (Billable) - R53.83 — Other fatigue (Billable) - R55 — Syncope and collapse (Billable) - R73.03 — Prediabetes (Billable) ### Injury & Poisoning (Chapter 19: S00–T88) - S06.0X0A — Concussion without loss of consciousness, initial encounter (Billable) - S72.001A — Fracture of unspecified part of neck of right femur, initial encounter (Billable) - T78.40XA — Allergy, unspecified, initial encounter (Billable) - T81.4XXA — Infection following a procedure, initial encounter (Billable) ### External Causes (Chapter 20: V00–Y99) - W19.XXXA — Unspecified fall, initial encounter (Billable) - Y83.1 — Surgical operation with implant of artificial internal device (Billable) ### Factors Influencing Health Status (Chapter 21: Z00–Z99) - Z00.00 — Encounter for general adult medical examination without abnormal findings (Billable) - Z00.129 — Encounter for routine child health examination without abnormal findings (Billable) - Z01.00 — Encounter for examination of eyes and vision without abnormal findings (Billable) - Z12.11 — Encounter for screening for malignant neoplasm of colon (Billable) - Z12.31 — Encounter for screening mammogram for malignant neoplasm of breast (Billable) - Z20.822 — Contact with and (suspected) exposure to COVID-19 (Billable) - Z23 — Encounter for immunization (Billable) - Z51.11 — Encounter for antineoplastic chemotherapy (Billable) - Z79.4 — Long term (current) use of insulin (Billable) - Z79.82 — Long term (current) use of aspirin (Billable) - Z79.899 — Other long term (current) drug therapy (Billable) - Z85.3 — Personal history of malignant neoplasm of breast (Billable) - Z87.891 — Personal history of nicotine dependence (Billable) - Z96.1 — Presence of intraocular lens (Billable) --- ## Common Coding Scenarios ### Diabetes Mellitus Use E10.– for Type 1, E11.– for Type 2, E13.– for other specified diabetes. Always code to the highest specificity for the complication: - Unspecified: E11.9 - With nephropathy: E11.21 - With chronic kidney disease: E11.22 (also assign N18.– for CKD stage) - With neuropathy: E11.40 - With hyperglycemia: E11.65 - With foot ulcer: E11.621 (also assign L97.– for ulcer severity/site) Use Z79.4 as an additional code for long-term insulin use in Type 2 patients. ### Hypertension - Essential hypertension alone: I10 - With heart disease: I11.– (I11.0 with heart failure, I11.9 without) - With CKD: I12.– (assumes causal relationship per ICD-10 guidelines) - With both heart disease and CKD: I13.– - Always assign additional codes for CKD stage (N18.–) and heart failure type (I50.–) ### COPD & Asthma - COPD without exacerbation: J44.9 - COPD with acute exacerbation: J44.1 - COPD with lower respiratory infection: J44.0 (also code the infection) - Asthma: J45.– with 4th character for severity, 5th for complications - Asthma with COPD: Assign both J44.– and J45.– codes ### Heart Failure Systolic vs. diastolic vs. combined: - Systolic (HFrEF): I50.2– - Diastolic (HFpEF): I50.3– - Combined: I50.4– Acuity: acute (x0), chronic (x2), acute on chronic (x3) Example: Acute on chronic systolic heart failure = I50.23 ### Chronic Kidney Disease (CKD) Assign both the CKD stage code and the underlying cause: - Stage 1: N18.1 (GFR ≥90) - Stage 2: N18.2 (GFR 60–89) - Stage 3: N18.3 (GFR 30–59) - Stage 4: N18.4 (GFR 15–29) - Stage 5: N18.5 (GFR <15) - ESRD: N18.6 (on dialysis or awaiting transplant) --- ## Premium Features (Free Trial Available) ICD-10 Coding Pro offers additional tools for professional medical coders: - **HCC Risk Adjustment Mappings** — CMS-HCC V24, V28, and RxHCC model mappings for every applicable diagnosis code. Essential for Medicare Advantage risk adjustment coding. - **FDA Drug Indications** — Diagnosis codes linked to FDA-approved drug indications. See which medications are associated with each diagnosis. - **AI Coding Assistant** — Natural-language code lookup powered by AI. Describe a clinical scenario and get recommended ICD-10-CM codes with rationale. - **AHA Coding Clinic References** — Official coding guidance from the American Hospital Association linked to relevant codes. - **Project Guidelines** — Upload your organization's coding guidelines and get AI assistance that follows your specific rules. 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