ICD-9 coding

Use of specific diagnoses improves the quality of claims and is just as important as CPT coding.

During an internal chart review, the compliance committee noted several diagnosis coding errors. They included incompleteness, inaccuracy and sometimes what appeared to be intentional abuse. The committee determined that recent turnover at the checkout desk and in the billing office resulted in a lack of understanding of proper use of diagnosis (ICD-9) codes and its significance. For the physicians and the technical staff, coding was all about picking the right CPT code(s). As a result, diagnosis coding received a lot less attention. These errors required immediate attention to improve claims and compliance.

What issues need addressing to improve ICD-9 code selection?

Physicians and staff need to know how to locate the appropriate diagnosis code in the manual. It is easiest to first look in the alphabetical listing (ie, glaucoma) and secondarily in the tabular listing (ie, 365.xx). The tabular listing provides more detailed explanations and guidance. It further stratifies glaucoma disease to various levels of specificity, providing up to five digits (eg, 365.11 – Primary open-angle glaucoma). The first three digits describe the location and category of disease; the fourth and fifth digits elaborate on the description. Use of specific diagnoses improves the quality of claims, may support higher levels of service and reduces claim denials.

The reason for the service, as described on the claim for reimbursement by the diagnosis code, determines coverage by the third-party payer. Limitations of coverage and reimbursement exist because policies exclude some ICD-9 codes. For example, Medicare does not pay for exams for routine vision care (V72.0) or to cope with refractive errors (367.xx). If a Medicare beneficiary’s chief complaint is “wants new eyeglasses,” then this exam will not be covered.

The diagnosis code should comport with the reason for the patient’s visit as described in the chief complaint. For example, if the patient’s chief complaint is “3-month follow-up of chronic open-angle glaucoma in both eyes,” the primary diagnosis code should be 365.11 (COAG). If this patient’s history also includes cataracts and age-related macular degeneration, these added diagnoses are subordinated or omitted altogether. Without a complaint to correlate with cataracts and AMD, these conditions may not be particularly relevant to today’s encounter. The ICD-9 guidelines instruct users to list chronic conditions or secondary diagnoses only if pertinent to the visit.

It is not uncommon to see an assessment that reads “probable, suspect, rule out or undefined disorder.” Claim submission requires a diagnosis code; however, no such codes exist to describe a probable condition or rule out status.

The introduction to the ICD-9 manual addresses this issue by stating, “Diagnoses documented as ‘probable,’ ‘suspected,’ ‘questionable,’ or ‘rule out,’ should not be coded as if the diagnosis is confirmed … code to the highest degree of certainty, such as describing symptoms, signs, abnormal test results, or other reasons for the encounter.” It also states, “Codes that describe symptoms as opposed to diagnoses are acceptable if this is the highest level of certainty documented by the physician.” Code the symptoms in the absence of a definitive diagnosis.

Patients with systemic disease such as diabetes or patients taking high-risk medications (ie, Plaquenil) often present with no ocular manifestations of their systemic disease, but an eye exam is medically necessary. These claims utilize the systemic disease as the primary diagnosis.

Patients return for follow-up exams so a physician can assess their progress for treated conditions. During the course of treatment, diagnosis coding is straightforward. When the condition no longer exists, the ICD-9 introduction states, “Do not include codes for conditions that were previously treated and no longer exist.”

For example, a malignant lesion is removed from the patient’s eyelid. All margins are clear, and the physician reports that no further malignancy exists at this time. The patient returns 6 months after the excision with no problems or complaints for a follow-up check. The area remains clear with no signs of re-growth. It is inappropriate to code today’s visit with a malignant lesion diagnosis. The correct ICD-9 is V10.83, Personal history of malignant neoplasm, skin.

The new staff at the checkout desk or in the billing office may not necessarily know which diagnosis is associated with which service. Match them up by drawing a line between the CPT code and the ICD-9 code to make the association.

Beneficiaries can become agitated and confrontational when told that the coverage of their health plan does not pay for some services. It might be tempting to change the diagnosis on the claim form to prevent a denial, but do not do that. Willfully and knowingly filing a deceptive claim for reimbursement is fraud. Addressing these issues with staff improves compliance and the accuracy of claims.