When we coders and auditors talk about the selection of the principal diagnosis, we know that the first diagnosis reported on a claim is the most important, because sometimes it’s the only one that payers will see. But one diagnosis code does not tell the full story of a patient. That’s why reporting additional diagnoses is highly recommended, and sometimes even necessary.
ICD-10-CM Guideline Section III recommends reporting additional diagnoses when the condition affects patient care by requiring any of the following:
- Clinical evaluation
- Therapeutic treatment
- Diagnostic procedures
- Extended length of hospital stay
- Increased nursing care and/or monitoring
For example, a patient in a Skilled Nursing Facility (SNF) has a primary diagnosis of congestive heart failure (CHF). She also has pressure ulcers that require frequent monitoring and debridement. When submitting the claim for SNF care, use the CHF as the primary diagnosis and the diagnosis code(s) for the site, and stage of the pressure ulcers as the secondary.
The guideline states that the listing of the diagnoses in the patient record is the responsibility of the provider. Therefore, coders should only reorder diagnoses if ICD-10 guidelines or notes require them. Typically, if a provider has included a diagnosis in the assessment and plan, or the discharge summary, it should be coded. You may need to query a provider if it is unclear if the condition truly still exists. Coders can also reorder diagnoses on the pro-fee side in cases where it may help substantiate the services performed.
For example, if a patient presents for evaluation and management of their hypertension, and has a mole requiring removal, the hypertension would be the primary diagnosis on the E/M CPT code, and the code for the mole would be the primary diagnosis for the procedure.
In an inpatient-type setting, abnormal diagnostic findings (laboratory, radiology, etc.) are not reported unless they have an impact on care. The reason for ordering the test is the diagnosis reported. This differs in the outpatient/clinic setting, where the provider may report an abnormal finding if it requires additional work-up, such as an abnormal mammogram that may require more testing.
It is important not to code diagnoses that have no bearing on the current service. A patient that is being seen by a psychiatrist for depression also has a family history of melanoma. The psychiatrist is neither treating or addressing the melanoma history; but perhaps it was simply stated in the family history section of the note. Therefore, the code for this should not be reported on the claim, as it has no effect on that day’s service.
Equally important is reporting codes that have resolved. Neoplasm coding is the most frequently used in error here. Let’s say a patient had breast cancer 10 years ago, has no lasting clinical conditions, and is no longer on any treatment, a code from Chapter 2: Neoplasms should not be used. Instead, append code Z85.3, history of malignant neoplasm of the breast IF it affects patient care by the criteria above.
There are many instances in ICD-10-CM where an additional code is required. This is the “use additional code” and “code first” notes. In these cases, you must list the underlying condition first, followed by the manifestation (see ICD-10-CM Guideline I.A.13 for more information).
Many payers will accept up to 12 diagnoses on a claim. It does take some time to select 12 diagnoses! So, my advice is to balance the time with reporting the diagnoses that take precedence. This will ensure you are telling the full story of the patient’s care.