The International Classification of Diseases, 10th Revision (ICD-10) is the coding system used by healthcare providers to document diagnoses. With over 70,000 codes, precise ICD-10 coding is critical to successful reimbursement.
ICD-10-CM vs. ICD-10-PCS
There are two main ICD-10 code sets:
- ICD-10-CM (Clinical Modification) — Used by all providers for diagnosis coding on outpatient and inpatient claims.
- ICD-10-PCS (Procedure Coding System) — Used by hospitals for inpatient procedure coding only.
Key Coding Principles
Code to the Highest Level of Specificity
ICD-10 codes can be 3–7 characters long. Always code to the highest level of specificity supported by the documentation. Unspecified codes should only be used when documentation genuinely does not support a more specific code.
Laterality Matters
Many musculoskeletal and sensory codes require laterality (left, right, bilateral). Missing laterality is a common cause of rejections — always capture it from the clinical notes.
Sequencing Rules
The principal diagnosis (the condition chiefly responsible for the encounter) must be sequenced first. Secondary diagnoses, comorbidities, and complications follow in order of significance.
Common ICD-10 Coding Mistakes
- Using placeholder "X" incorrectly in injury codes
- Combining codes that should not appear together (Excludes1 notes)
- Failing to capture external cause codes for injuries
- Using outdated codes after annual October updates
Staying Current
ICD-10-CM codes are updated every October 1st. Practices must update their EHR and billing systems before the effective date and re-train coding staff on new additions and deletions.
Radiant RCM's certified coders stay current with every annual update, ensuring your claims reflect the latest code set. Reach out to our team to learn how we handle coding accuracy for your specialty.