Q&A: When is combination code reporting permitted?

Q: I was wondering what supporting evidence there is for the recommendation to go ahead and link hypertension (HTN) with heart failure as a combination code? The Official Guideline for Coding and Reporting as well as Coding Clinic for ICD-9-CM seems to indicate not to combine these without an expressed link by the physician. Renal disease is an assumed link, but not heart disease. I’d also like to know the thought process behind tracing this diagnosis to DRG 316 for stress-related chest pain. When I code chest pain with anxiety or acute stress reaction I get DRG 880 or 882.

A: A combination code is a single code used to classify:

• Two diagnoses, or
• A diagnosis with an associated secondary process (manifestation)
• A diagnosis with an associated complication

Combination codes are identified by referring to sub-term entries in the Alphabetic Index and by reading the inclusion and exclusion notes in the Tabular List. Coders should only assign the combination code when that code fully identifies the diagnostic conditions involved or when the Alphabetic Index so directs. Multiple coding should not be used when the classification provides a combination code that clearly identifies all of the elements documented in the diagnosis. When the combination code lacks necessary specificity in describing the manifestation or complication, an additional code should be used as a secondary code.

To simplify if a physician documents two conditions as being related to each and there is a combination code, the combination code should be used instead of two separate codes.

The code that relates to stress related chest pain is code 306.2 cardiovascular malfunction arising from mental factors, which groups to DRG 316.

Editor's note: Fran Jurcak, RN, MSN, CCDS, at the time of this article's release, was a manager with Wellspring Partners, a division of Huron Consulting, and has been a nurse for 25 years. She has a strong clinical and educational background having served as a professor of nursing for many years.