Typically, when coding, billing, and documentation are discussed, most people think of Current Procedural Terminology (CPT) and Healthcare Common Procedure Coding System (HCPCS) codes. However, the diagnosis codes from the International Classification of Diseases, 10th Revision (ICD-10-CM), included in the chart and the claim, are equally important. This month’s column answers some questions about diagnosis coding.
Q. How do diagnosis codes support medical necessity?
A. Defining “medical necessity” poses challenges, with various interpretations among payers. However, as specified in Title XVIII of the Social Security Act, Section 1862(a)(1)(A), “…no payment may be made for any expenses incurred for items or services, which are not reasonable and necessary for the diagnosis or treatment of injury or to improve the functioning of a malformed body member.” As such, the first consideration in reviewing all services is medical necessity.
Payers employ claim edits to assess claims with automated commands for denial or review. These edits ensure payment for specific procedure codes when administered to patients with a designated diagnosis code or a predetermined range of diagnosis codes. The diagnosis code should support what was done to or for the patient, because the codes succinctly describe the patient’s diagnosis or medical condition. This information is essential for understanding why specific healthcare services are necessary.
Q. What does “to the highest specificity” mean?
A. ICD-10 is divided into categories, subcategories, and codes. The most common categories in retina are the E codes (diabetic) and H codes (eye and adnexa). Most diagnosis codes extend to 7 characters. However, a few in retina are 5 characters (for example, H43.89 Other disorders of vitreous body).
The eye indicator should always be for the right eye (1), left eye (2), or bilateral (3). The placement of the eye indicator changes between the E codes and the H codes, which can cause confusion (Table 1). While there is an unspecified eye (9) indicator, the diagnosis code is not to the highest specificity if it is used.
Q. Can a bilateral diagnosis code be used for a unilateral intravitreal injection if both eyes are treated, but not on the same day?
A. The injection procedure should reflect the eye and the corresponding diagnosis and agree with the diagnosis codes in the Impression and Plan (I/P) for the service date. For example, the documentation would not be to the highest specificity if a unilateral injection had a bilateral diagnosis code if both eyes were not injected on the same day. The I/P can have a bilateral diagnosis if each eye’s treatment plan is clearly documented. Ultimately, the documentation for the procedure eye should match the diagnosis code.
Q. What are some common errors to watch for?
A. Transposing numbers in a diagnosis code can quickly change the meaning and medical necessity. For example, H35.3213 is “Exudative age-related macular degeneration, right eye, with inactive scar,” and H35.3123 is “Nonexudative age-related macular degeneration, left eye, advanced atrophic without subfoveal involvement.” Switching the 5th and 6th characters creates a different diagnosis code that may cause a claim denial due to lack of medical necessity.
Conclusion
The medical record is a legal document that supports the physician’s services to a patient. And because it is a legal record, the integrity of the chart document is imperative to ensure safe and effective patient care that is properly reimbursed. Following best practices and providing continuing education for staff can improve the accuracy of medical documentation at your retina clinic. RP
