Professional ICD-10 Diagnosis Coding Services
Used to identify patient diagnoses, ICD-10-CM codes describe the medical condition or reason for a patient’s visit. Maintained by the Centers for Disease Control and Prevention (CDC), these codes support medical necessity and proper claim processing.
Complete Guide to ICD-10-CM Codes and Medical Diagnosis Coding
ICD-10-CM (International Classification of Diseases, Tenth Revision, Clinical Modification) is used to identify patient diagnoses, medical conditions, and reasons for healthcare visits. Accurate ICD-10 coding is essential for correct reimbursement, compliance with payer policies, and proper medical necessity documentation.
Maintained by the Centers for Disease Control and Prevention (CDC) and the National Center for Health Statistics (NCHS), these codes describe the medical condition or reason for a patient’s visit and support medical necessity for procedures and treatments. Our expert coders ensure each diagnosis is coded accurately based on clinical documentation and current coding guidelines.
Benefits of Accurate ICD-10 Coding
Understanding ICD-10-CM Code Structure
ICD-10-CM codes are alphanumeric and can contain 3 to 7 characters. The code structure provides specific information about the diagnosis:
- 1st character: Always a letter indicating the chapter or body system
- 2nd character: Always a number
- 3rd character: Number or letter (forms the category)
- 4th-7th characters: Provide additional specificity regarding etiology, anatomical site, severity, and other clinical details
Most Commonly Used ICD-10 Codes by Category
Cardiovascular Diseases
Cardiovascular conditions are among the most frequently diagnosed chronic diseases in primary care and specialty practices.
| Code | Description |
| I10 | Essential (primary) hypertension |
| I11.0 | Hypertensive heart disease with heart failure |
| I11.9 | Hypertensive heart disease without heart failure |
| I12.0 | Hypertensive chronic kidney disease with stage 5 CKD or ESRD |
| I12.9 | Hypertensive chronic kidney disease with stage 1-4 or unspecified CKD |
| I13.0 | Hypertensive heart and chronic kidney disease with heart failure and stage 1-4 CKD |
| I13.10 | Hypertensive heart and chronic kidney disease without heart failure with stage 1-4 CKD |
| I13.11 | Hypertensive heart and chronic kidney disease without heart failure with stage 5 CKD or ESRD |
| I25.10 | Atherosclerotic heart disease of native coronary artery without angina pectoris |
| I25.110 | Atherosclerotic heart disease of native coronary artery with unstable angina pectoris |
| I25.111 | Atherosclerotic heart disease of native coronary artery with angina pectoris with documented spasm |
| I25.118 | Atherosclerotic heart disease of native coronary artery with other forms of angina pectoris |
| I25.119 | Atherosclerotic heart disease of native coronary artery with unspecified angina pectoris |
| I25.2 | Old myocardial infarction |
| I21.9 | Acute myocardial infarction unspecified |
| Code | Description |
| I50.1 | Left ventricular failure unspecified |
| I50.20 | Unspecified systolic (congestive) heart failure |
| I50.21 | Acute systolic (congestive) heart failure |
| I50.22 | Chronic systolic (congestive) heart failure |
| I50.23 | Acute on chronic systolic (congestive) heart failure |
| I50.30 | Unspecified diastolic (congestive) heart failure |
| I50.9 | Heart failure unspecified |
| I48.0 | Paroxysmal atrial fibrillation |
| I48.1 | Persistent atrial fibrillation |
| I48.2 | Chronic atrial fibrillation |
| I48.91 | Unspecified atrial fibrillation |
Endocrine, Nutritional, and Metabolic Diseases
| Code | Description |
| E11.9 | Type 2 diabetes mellitus without complications |
| E11.65 | Type 2 diabetes mellitus with hyperglycemia |
| E11.641 | Type 2 diabetes mellitus with hypoglycemia with coma |
| E11.649 | Type 2 diabetes mellitus with hypoglycemia without coma |
| E11.21 | Type 2 diabetes mellitus with diabetic nephropathy |
| E11.22 | Type 2 diabetes mellitus with diabetic chronic kidney disease |
| E11.29 | Type 2 diabetes mellitus with other diabetic kidney complication |
| E11.311 | Type 2 diabetes mellitus with unspecified diabetic retinopathy with macular edema |
| E11.319 | Type 2 diabetes mellitus with unspecified diabetic retinopathy without macular edema |
| E11.40 | Type 2 diabetes mellitus with diabetic neuropathy unspecified |
| E11.42 | Type 2 diabetes mellitus with diabetic polyneuropathy |
| E11.51 | Type 2 diabetes mellitus with diabetic peripheral angiopathy without gangrene |
| E11.52 | Type 2 diabetes mellitus with diabetic peripheral angiopathy with gangrene |
| E10.9 | Type 1 diabetes mellitus without complications |
| E10.65 | Type 1 diabetes mellitus with hyperglycemia |
| E78.5 | Hyperlipidemia unspecified |
| E78.0 | Pure hypercholesterolemia |
| E78.1 | Pure hyperglyceridemia |
| E78.2 | Mixed hyperlipidemia |
| E78.3 | Hyperchylomicronemia |
| E78.4 | Other hyperlipidemia |
| Code | Description |
| E03.9 | Hypothyroidism unspecified |
| E03.0 | Congenital hypothyroidism with diffuse goiter |
| E05.90 | Thyrotoxicosis unspecified without thyrotoxic crisis |
| E06.3 | Autoimmune thyroiditis |
| E66.9 | Obesity unspecified |
| E66.01 | Morbid (severe) obesity due to excess calories |
| E66.1 | Drug-induced obesity |
| E66.2 | Morbid (severe) obesity with alveolar hypoventilation |
| E66.3 | Overweight |
| E55.9 | Vitamin D deficiency unspecified |
Respiratory System Diseases
| Category | ICD-10 Code | Description | |
| Upper Respiratory Infections | J06.9 | Acute upper respiratory infection | unspecified |
| Upper Respiratory Infections | J02.9 | Acute pharyngitis | unspecified |
| Upper Respiratory Infections | J02.8 | Acute pharyngitis due to other specified organisms | |
| Upper Respiratory Infections | J00 | Acute nasopharyngitis (common cold) | |
| Upper Respiratory Infections | J01.90 | Acute sinusitis | unspecified |
| Upper Respiratory Infections | J01.00 | Acute maxillary sinusitis | unspecified |
| Upper Respiratory Infections | J32.9 | Chronic sinusitis | unspecified |
| Lower Respiratory Infections | J20.9 | Acute bronchitis | unspecified |
| Lower Respiratory Infections | J20.0 | Acute bronchitis due to Mycoplasma pneumoniae | |
| Lower Respiratory Infections | J20.1 | Acute bronchitis due to Hemophilus influenzae | |
| Lower Respiratory Infections | J20.2 | Acute bronchitis due to streptococcus | |
| Lower Respiratory Infections | J18.9 | Pneumonia | unspecified organism |
| Lower Respiratory Infections | J18.1 | Lobar pneumonia | unspecified organism |
| Chronic Respiratory Conditions | J44.9 | Chronic obstructive pulmonary disease | unspecified |
| Chronic Respiratory Conditions | J44.0 | Chronic obstructive pulmonary disease with acute lower respiratory infection | |
| Chronic Respiratory Conditions | J44.1 | Chronic obstructive pulmonary disease with acute exacerbation | |
| Chronic Respiratory Conditions | J45.909 | Unspecified asthma | uncomplicated |
| Chronic Respiratory Conditions | J45.901 | Unspecified asthma with acute exacerbation | |
| Chronic Respiratory Conditions | J45.20 | Mild intermittent asthma | uncomplicated |
| Chronic Respiratory Conditions | J45.30 | Mild persistent asthma | uncomplicated |
| Chronic Respiratory Conditions | J45.40 | Moderate persistent asthma | uncomplicated |
| Chronic Respiratory Conditions | J45.50 | Severe persistent asthma | uncomplicated |
Digestive System Diseases
| Category | ICD-10 Code | Description | ||
| Gastroesophageal Reflux | K21.9 | Gastro-esophageal reflux disease without esophagitis | ||
| Gastroesophageal Reflux | K21.0 | Gastro-esophageal reflux disease with esophagitis | ||
| Gastritis and Peptic Ulcer | K29.70 | Gastritis | unspecified | without bleeding |
| Gastritis and Peptic Ulcer | K29.71 | Gastritis | unspecified | with bleeding |
| Gastritis and Peptic Ulcer | K27.9 | Peptic ulcer | site unspecified | unspecified as acute or chronic |
| Irritable Bowel Syndrome | K58.9 | Irritable bowel syndrome without diarrhea | ||
| Irritable Bowel Syndrome | K58.0 | Irritable bowel syndrome with diarrhea | ||
ICD-10 Coding Best Practices
Common ICD-10 Coding Mistakes to Avoid
Using Unspecified Codes When Specificity is Available
While unspecified codes are valid, they should only be used when specific information is truly not documented or not clinically determinable.
Coding Symptoms When Diagnosis is Known
Do not code symptoms separately when a definitive diagnosis has been established, unless the symptom is not routinely associated with the diagnosis.
Incorrect Laterality
Many ICD-10 codes require specification of right, left, bilateral, or unspecified. Failing to specify laterality when required will result in claim rejection.
Missing Seventh Characters
Forgetting to add required seventh characters or using incorrect characters is a common error that leads to claim denials.
Outdated Codes
Using codes from previous years after annual updates have taken effect will result in claim rejections.
Insufficient Documentation
Coding beyond what is documented in the medical record creates compliance risks and potential fraud allegations.
Contact Us for Professional ICD-10 Coding Services
Our team of certified professional coders brings extensive experience across all medical specialties and healthcare settings. We understand the complexities of ICD-10 diagnosis coding and work diligently to ensure your practice receives accurate reimbursement while maintaining compliance.
Whether you need ongoing coding support, coding audits, provider education, or help with specialty-specific diagnosis coding challenges, our experts are ready to assist your practice in achieving coding excellence and optimal reimbursement.
Transform Your Medical Billing with Expert ICD-10 Coding
Whether you need ongoing coding support, coding audits, provider education, or help with specific specialty coding challenges, our experts are ready to assist your practice in achieving coding excellence.
