In the healthcare industry, medical coding is the linchpin of clinical documentation, billing, and statistical analysis. Among the coding systems, ICD-10 (International Classification of Diseases, 10th Revision) stands out due to its extensive code set and detailed structure. While it significantly enhances documentation specificity and healthcare analytics, it also introduces a greater risk of errors for coders and healthcare providers.
These mistakes not only disrupt the revenue cycle but also put organizations at risk of non-compliance and inaccurate clinical data. In this blog, we’ll uncover five of the most common ICD-10 coding mistakes and provide practical tips to help you avoid them. Whether you're a seasoned coder, a physician, or a healthcare administrator, these insights will enhance your understanding and accuracy in using ICD-10.
1. Lack of Specificity in Code Selection
The Mistake:
One of the most frequent ICD-10 errors is using unspecified or generalized codes when more specific options are available. ICD-10 offers a detailed hierarchy of diagnosis codes, with many codes going down to the sixth or seventh character for precision.
For example, coding “J18.9 – Pneumonia, unspecified organism” when documentation supports “J13 – Pneumonia due to Streptococcus pneumoniae” reflects a lack of specificity.
Why It Matters:
Lack of specificity can lead to claim denials and reduce the value of data used in clinical decision-making and public health reporting.
How to Avoid It:
Train coding staff to identify opportunities for specificity.
Collaborate with physicians to improve documentation.
Implement clinical documentation improvement (CDI) programs to ensure relevant details are captured.
2. Incorrect Use of 7th Characters
The Mistake:
ICD-10 introduced the 7th character extension for certain chapters, particularly in injury, obstetrics, and musculoskeletal conditions. The most common error is using the wrong 7th character or forgetting to include it altogether.
For example, the fracture code “S52.501” is incomplete without a 7th character like “A” (initial encounter) or “D” (subsequent encounter), resulting in invalid claims.
Why It Matters:
A missing or incorrect 7th character can render the entire code invalid, leading to rejections or audits.
How to Avoid It:
Use coding tools that alert users when a 7th character is required.
Memorize the meanings of the most common 7th characters.
Always consult the official ICD-10 guidelines or a coding software that supports ICD-10 extensions.
3. Overuse of “Unspecified” Codes
The Mistake:
Using unspecified codes (like “I10 – Essential hypertension, unspecified”) is sometimes necessary but often overused due to convenience or lack of documentation.
Why It Matters:
Frequent use of unspecified codes can raise red flags with payers and affect a healthcare organization’s quality scores and reimbursement.
How to Avoid It:
Only use unspecified codes when clinical documentation truly lacks the necessary detail.
Educate providers on the financial and operational impact of under-documenting patient encounters.
Develop checklists for common conditions to prompt physicians for details.
4. Coding Symptoms Instead of Diagnoses
The Mistake:
This occurs when coders or providers document and code symptoms (e.g., cough, chest pain) even when a definitive diagnosis is already available.
Why It Matters:
ICD-10 guidelines clearly state that symptom codes should not be reported when a definitive diagnosis is established. This mistake can result in claim rejections and misrepresent the patient’s condition.
How to Avoid It:
Carefully review documentation to determine if a confirmed diagnosis exists.
Code the confirmed condition, not the presenting symptoms.
Educate clinical staff on documentation practices that avoid ambiguous statements.
5. Using Outdated or Inactive Codes
The Mistake:
ICD-10 codes are updated annually. Using outdated or deleted codes, often due to using old software or outdated reference materials, is a surprisingly common error.
Why It Matters:
Outdated codes can result in claim rejections and compliance issues during audits.
How to Avoid It:
Use updated coding software that includes the latest ICD-10 updates.
Subscribe to CMS, AAPC, or AHIMA newsletters to stay informed about annual changes.
Set a calendar reminder each October (when ICD-10 updates take effect) to review and apply code changes.
Final Thoughts
ICD-10 offers immense benefits for medical coding accuracy, healthcare analytics, and patient care, but its complexity also introduces new challenges. These five common mistakes—lack of specificity, misuse of 7th characters, overreliance on unspecified codes, symptom coding errors, and outdated code usage—can seriously affect your bottom line and operational efficiency.
To stay ahead:
Invest in regular coder training.
Collaborate across clinical and billing teams.
Use modern coding software and regularly update your codebase.
The key to success in ICD-10 coding is proactivity. By being detail-oriented and staying updated, you’ll ensure that your coding is not just compliant—but a strong contributor to quality healthcare delivery.
About the Author:
John D. is a certified medical coding expert and the founder of ICD10Codes, where he provides simplified ICD-10 resources for coders, clinicians, and healthcare organizations. With over 10 years of experience in the field, John is passionate about improving documentation accuracy and medical coding standards across the industry. Based in Austin, Texas, he also collaborates with industry blogs and journals to spread coding best practices.
