Practice Economics

Response: Properly Coding an Uncertain Diagnosis


Dr. Pinson:

Thank you for your inquiry to my June column, which outlined physician reporting of ICD-9-CM diagnoses. Confusion arises because there are two mechanisms for reporting facility-based claims: the professional (physician) bill and the facility bill. ICD-9-CM has been adopted under HIPAA for all healthcare settings. Several components of the ICD-9-CM manual offer instructions on its use. “How to Use the ICD-9-CM for Physicians (Volumes 1&2)” identifies “10 Steps to Correct Coding.”2,3 Step 1 explicitly denotes the inability to use “rule out,” “suspected,” “probable,” or “questionable” diagnoses, and applies to all professional claims submitted on CMS1500 or electronic equivalent.3

The “ICD-9-CM Official Guidelines for Coding and Reporting” are a set of rules developed to accompany and complement the official conventions and instructions provided within ICD-9-CM and approved by the four organizations that make up the Cooperating Parties for the ICD-9-CM: the American Hospital Association (AHA), the American Health Information Management Association (AHIMA), the Centers for Medicare & Medicaid Services (CMS), and NCHS. These guidelines are included on the official government version of the ICD-9-CM, and also appear in “Coding Clinic for ICD-9-CM” published by the AHA.3

While Section I of these guidelines applies to all locations, Sections II and III refer to the selection of the principal diagnosis (the condition established after study to be chiefly responsible for the admission) reported by facilities for DRG payment on CMS1450 or its electronic equivalent.2 Since DRG payment is based on the average resources used to treat inpatients, it is allowable to code a properly documented, “uncertain” condition as if it existed or was established. It does not apply to the outpatient setting. Outpatient, facility-based (Section IV) claims follow the same standards as professional claims, which should not list any diagnosis documented as “probable,” “suspected,” “questionable,” “rule out” or “working diagnosis,” or other similar terms indicating uncertainty.

Carol Pohlig, BSN, RN, CPC, ACS, is a contributing writer to The Hospitalist.


  1. Hart AC, Stegman MS, Ford B, eds. ICD-9-CM for Physicians Volumes 1 & 2 2012 Expert Edition. OptimumInsight; 2011. Page vi.
  2. Centers for Medicare & Medicaid Services. Medicare Claims Processing Manual. Chapter 23, Section 10A. Centers for Medicare and Medicaid Services website. Available at: Accessed July 24, 2012.
  3. Hart AC, Stegman MS, Ford B. ICD-9-CM for Physicians Volumes 1 & 2 2012 Expert Edition. OptimumInsight; 2011. Page 1.

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