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Improper sequencing of the principal diagnosis is one of the problems uncovered by recovery audit contractors, according to the Centers for Medicare & Medicaid Services.

In addition to providing a list of resources where providers can learn more about this topic, CMS included the following two examples of selection of inappropriate codes in its October 2012 Medicare Quarterly Provider Compliance Newsletter.

Case Study 1

An 80-year-old female was admitted through the emergency department with ICD-9-CM code 414.01 (coronary Atherosclerosis, of native coronary artery) as the principal diagnoses, and 410.01 (acute myocardial infarction, of anterolateral wall, initial episode of care) as the secondary diagnosis.

She was taken urgently to the cardiac catheterization lab for angiography that revealed the following:

  • A normal left main coronary artery
  • A 99 percent occlusion of the proximal left anterior descending (LAD) coronary artery, and heavy calcification throughout its remainder, with a mid-course 50 percent lesion, and another 50 percent lesion distally
  • A large circumflex coronary artery with luminal irregularities, but no high-grade obstructions
  • A dominant right coronary artery with a proximal 50 percent stenosis and a mid-course 60 percent stenosis.

Following angiography, she underwent successful primary angioplasty to the proximal LAD lesion, and was begun on medical therapy for the rest of her coronary disease.

RAC Findings

The provider’s code assignments for principal and secondary diagnoses (414.01 and 410.01) (Acute Myocardial Infarction, of Anterolateral Wall, Initial Episode of Care). The recovery auditor reviewed the ED record, history and physical, progress notes, consultation reports, and clinical narrative and determined that the physician’s documentation did not support the principal diagnosis of 414.01 that the provider assigned. The auditor re-sequenced the acute myocardial infarction code (410.01) as the principal diagnosis.

This re-sequencing resulted in a MS-DRG change from 248 (percutaneous cardiovascular procedure with non-drug- eluting stent with MCC or 4+ vessels/stents) to MS-DRG 249 (percutaneous cardiovascular procedure with non-drug-eluting stent without MCC).

Case Study 2

A 76-year-old female admitted with an exacerbation of chronic obstructive pulmonary disease (COPD) and chest pain/angina with electrocardiographic changes was later determined to have had an non-ST segment elevation myocardial infarction (NSTEMI) secondary to 80 to 90 percent obstructive lesions in the proximal and mid LAD. She underwent a percutaneous transluminal coronary angioplasty (PTCA) with insertion of stents with no complications.

RAC Findings

This is another example of an error in sequencing the principal diagnosis. In this case, the provider assigned diagnosis code 414.01 (coronary atherosclerosis; of native coronary artery) as the principal diagnosis. However, based on the guidance in the American Hospital Association’s (AHA) Coding Clinic, Q2, 2001, pages 8–9), the acute myocardial infarction should have been assigned as the principal diagnosis.

So, the reviewer re-sequenced code 410.71 (AMI; subendocardial infarction; initial episode of care) as the principal diagnosis. This resulted in an MS-DRG change from 248 (percutaneous cardiovascular procedure with non-drug-eluting stent with MCC) to 249 (percutaneous cardiovascular procedure with non-drug-eluting stent without MCC).

How to Avoid These Errors

CMS provides the following guidelines and resources to help coding professionals avoid such errors in the future:

About the Author

Janis Oppelt is an editor with MedLearn Publishing, a division of Panacea Healthcare Solutions, Inc., St. Paul, MN.

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To comment on this article please go to editor@racmonitor.com


Janis Oppelt

Janis Oppelt was the former editorial director for MedLearn Publishing.

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