Revenue Cycle

Understand diagnosis coding to protect against auditor scrutiny

Recovery Auditor Report, February 19, 2009

When coding for outpatient procedures, coders should base the patient’s diagnosis on his or her medical condition. When a physician is unable to determine a diagnosis at the time of the visit, coders should determine the code based on the initial symptoms the patient experienced. Consider the following outpatient coding rules: 
  • Accurately report of ICD-9-CM diagnosis codes. For accurate reporting of ICD-9-CM diagnosis codes, the physician documentation should describe the patient’s condition, using terminology that includes specific diagnoses as well as symptoms, problems, or reasons related to this encounter. One area problem area several auditors uncovered when reviewing hospital charts was that coders were pulling diagnosis codes from patients’ past medical history to expand the list of diagnosis codes. This allowed the coders to bill for a more complex encounter. However, coders can not assume the past medical history diagnosis has a current affect on the current condition for which the patient receiving treatment. Unless the physician has a direct statement that the past medical condition or the medications the patient is taking for this past medical condition has a direct link on the treatment for the current encounter, coders should not code the past medical history conditions.
  • Capture chronic diseases. Coders may report chronic diseases treated on an ongoing basis as many times as the patient is receiving treatment and care for the condition(s).
  • Code all documented conditions that coexist. Code all documented conditions that coexist at the time of the encounter, and require or affect patient care treatment or management.Do not code conditions that a physician previously treated and no longer exists. However, coders may use history codes (V10–V19) as secondary codes when the historical condition or family history has an effect on current care or influences treatment.
In addition, consider the following inpatient coding rules.
  • Manage uncertain diagnoses. When a diagnosis documented at the time of discharge is qualified as “probable,” “suspected,” “likely,” “questionable,” “possible,” or “still to be ruled out,” coders should report the condition as if it existed or was established. The basis for this guideline is the diagnostic workup, arrangements for further workup or observation, and initial therapeutic approach that correspond most closely with the established diagnosis. HHS defines other diagnoses as:
All conditions that coexist at the time of admission, that develop subsequently, or that affect the treatment received and/or the length of stay. Diagnoses that relate to an earlier episode which have no bearing on the current hospital stay are to be excluded.
  • Handle “other diagnoses.” For reporting purposes, the definition for other diagnoses is interpreted as additional conditions that affect patient care in terms of requiring one of the following:

    • Clinical evaluation
    • Therapeutic treatment
    • Diagnostic procedures
    • Extended length of hospital stay
    • Increased nursing care and/or monitoring

  • Consider final diagnostic statements. If a physician has included a diagnosis in the final diagnostic statement, such as the discharge summary or the face sheet, coders should ordinarily code it. However, some physicians include resolved conditions or diagnoses and status-post procedures from previous admission that have no bearing on the current stay in the diagnostic statement. Coders should not report these conditions. Consider the following examples:

    • When a patient is a smoker and the patient is there for a sunburn, a tobacco abuse diagnosis is inappropriate
    • When a patient has Parkinson’s disease and is coming for a wart on the finger, Parkinson’s disease is inappropriate as a diagnosis
    • When a patient has depression and is coming in for sutures from falling off a bike, a depression diagnosis is inappropriate
    • When a patient has a history of a myocardial infarction (MI) seven years prior and the patient currently has a cold, a MI diagnosis is inappropriate

When coders neglect to follow coding rules, auditors can deny claims as not medically necessary or take back money accordingly. This is an area that RACs may focus on heavily.

Editor’s note: Thanks to Carol Coots, BS, CPC, CPC-H, CEO of Indianapolis-based Medical Consulting From A to Z, for providing this information.

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