ICD-10

The International Classification of Diseases, 10th Revision, is the coding system used to describe diagnoses and the reasons for healthcare services.

ICD-10 codes describe why you saw the patient. While CPT codes describe what you did, ICD-10 codes describe the medical reason behind it. Every claim needs both: a procedure code and a diagnosis code that justifies why the procedure was medically necessary. The United States uses ICD-10-CM (Clinical Modification) for diagnosis coding and ICD-10-PCS (Procedure Coding System) for inpatient hospital procedure coding. As an outpatient provider, you are using ICD-10-CM. The full codeset contains over 70,000 unique diagnosis codes, which is a dramatic increase from the roughly 14,000 codes in the old ICD-9 system. ICD-10 codes are alphanumeric, starting with a letter followed by two digits, then a decimal point, and then up to four more characters for specificity. For example, E11.65 is type 2 diabetes with hyperglycemia. The more specific the code, the better it communicates the clinical picture to the payer. Proper diagnosis coding matters for credentialing because it affects your claims data profile. If your ICD-10 coding does not support the medical necessity of the services you bill, you will get denials. Consistent denials for medical necessity can trigger a payer audit, and audit findings can affect your network participation at re-credentialing time. Common ICD-10 coding errors include: using unspecified codes when a more specific code is available, failing to code to the highest level of specificity, using rule-out diagnoses on outpatient claims (you code the symptom, not the suspected diagnosis), and not updating diagnosis codes when the patient's condition changes. ICD-10 is updated every October 1. New codes are added and existing codes may be modified or deleted. Your billing staff or coder should review the updates annually and update your encounter form or EHR accordingly.