Coding Secondary Diagnoses for Outpatient Encounters

This Coding Tip is intended to provide guidance regarding coding and reporting of secondary diagnoses for outpatient encounters.

In many instances, secondary and/or chronic conditions are not reported for outpatient encounters, but failing to report these diagnoses does not paint a complete picture of the patient or result in appropriate reimbursement. It is very important that codes for all secondary diagnoses/statuses/histories, that are documented by the provider to be affecting patient management/treatment, be reported on the outpatient claim.

Just remember that all chronic conditions and histories must be documented in the record somewhere besides the history section. Coders should not be coding soley from the past medical history, past surgical history, family history, social history, or medication lists.

ICD-10-CM Official Guidelines for Coding and Reporting

ICD-10-CM provides guidelines specifically for coding outpatient encounters. These guidelines are provided for use by facilities and providers. Below, we will discuss a few of the guidelines for outpatient reporting.

• Reporting signs and symptoms: Codes for signs and symptoms are acceptable if a related definitive diagnosis has not been established by the provider (see ICD-10-CM coding guidelines I.B.4/IV.D).
  
  If a related diagnosis has been established and is linked to the signs/symptoms, assign only the code for the diagnosis.
  
  If a diagnosis has been established but is not linked to the signs/symptoms assign codes for both the diagnosis and the signs/symptoms as these may need further workup.
  
  Examples
  • Patient presents to the emergency department with chest pain and arm pain. The final diagnosis is 1). Chest pain; 2.) GERD. Since the physician has documented the symptom of chest pain without linking it to the diagnosis of GERD both the symptom of chest pain and the diagnosis of GERD would be reported. The coder should not assume that the chest pain is due to the GERD.
  • If the final diagnosis for the same patient as above is 1). GERD. Only a diagnosis code for GERD would be reported. A code for chest pain is not assigned.

• Encounters for Circumstances Other Than a Disease or Injury: Codes Z00-Z99 are available in Chapter 21 of ICD-10-CM to report patient history or status other than a disease or injury (see ICD-10-CM coding guidelines IV.E). If a patient’s history or status has an impact on or influences care and/or treatment the appropriate Z code should be reported.
  
  Example
  • Patient presents to the ED for difficulty breathing. The patient has COPD and a history of smoking. The provider’s final impression is COPD exacerbation, former smoker. In this case, a code for the COPD exacerbation would be reported as well as the “Z” code for personal history of smoking because the provider noted the history in the final impression.

• Chronic condition under current treatment: Chronic diseases treated on an ongoing basis may be coded and reported as many times as the patient receives treatment and care for the condition(s) (see ICD-10-CM coding guideline IV.I). To be reportable, management of these conditions should be documented in the record somewhere other than just the history, problem list and/or a medication list. It is the physician’s responsibility to document that the conditions are affecting the care and management of the patient for that encounter.
  
  Example
  • A patient with upper respiratory symptoms presents for evaluation. During the coding it is noted that the patient has a past medical history of HTN. However, the documentation within the current encounter’s progress note states the patient is no longer taking medications as the patient’s HTN is now controlled by diet and recent weight loss. The patient is diagnosed with URI and given antibiotics. Should HTN be coded? YES! The physician has documented in the progress note how the patient’s HTN is being managed. This is pertinent to the admission because many over the counter drugs for treating URI symptoms raise blood pressure just by using as directed.

Medical Necessity

Another reason to capture all reportable secondary diagnosis, history and status codes is to support medical necessity. Some payors will deny claims for outpatient testing if the corresponding ICD-10-CM codes do not meet medical necessity.

For example, if a patient with atrial fibrillation has an EKG performed during an outpatient encounter for fracture repair, and atrial fibrillation is documented as the reason for the EKG, but a code for atrial fibrillation is not assigned as a secondary diagnosis, the EKG charge/reimbursement may be denied by the payor.

Hierarchical Condition Categories (HCCs)

For Medicare Advantage Plan beneficiaries, certain ICD-10-CM codes are mapped to hierarchical condition categories or HCCs. HCC coding is designed to estimate future health care costs based on the complexity and severity of a patient’s chronic diagnoses. Each beneficiary is assigned a risk adjustment factor (RAF) score based on the HCCs their diagnoses map to. RAF scores are a numeric representation of the complexity of the patient’s chronic illnesses. If secondary diagnoses for all chronic conditions that are being managed by the provider are not reported, then HCCs are not captured for the claim. This may impact reimbursement and quality measure statistics. Below are some websites that explain the risk adjusted reimbursement methodology in more detail.

Learn more about Hierarchical Condition Categories (HCC’s) here:

• https://www.aapc.com/resources/what-is-risk-adjustment?msockid=0b8b6deb883762d62fa879f5898763c6
• https://www.cms.gov/medicare/payment/medicare-advantage-rates-statistics/risk-adjustment

Tips for Appropriately Capturing Secondary Diagnoses in the Outpatient Setting:

• Review orders to determine if additional signs, symptoms, or diagnoses are provided by the physician
• Report confirmed diagnoses on radiology and pathology reports (except for incidental findings) that have been interpreted by a physician.
• “Z” codes help paint the entire health picture for the patient. Report Z codes if their pertinence is documented somewhere besides just the past medical history.
• Sometimes it is the “Z” codes that will help meet medical necessity for outpatient testing.
• Code only confirmed diagnosis. Do not code for diagnoses documented in terms of uncertainty (e.g., probably, possible, suspected, to be ruled out, etc.).
• Report long-term use of medications when their impact has been noted in the documentation and not from the medication list alone.
• Chronic conditions should be reported on each visit when they are under treatment or are documented to be affecting the management of the patient on this encounter. Chronic systemic conditions will always affect patient management because of the need for continuous clinical monitoring and evaluation. For example, monitoring medications for interactions. Consideration of chronic conditions will almost always be part of the physician’s medical decision-making process, but the physician must still document how the condition was evaluated or managed for assignment of a code to be appropriate.
• Do not assign diagnosis codes based on the presence of up/down arrows on an order or MD note.
• Codes for any condition that requires treatment or monitoring may be reported regardless of whether the condition is chronic or acute as long as documentation supports evaluation/management or treatment of the condition.

Documentation Review

To ensure reporting of all reportable codes, coders should review the contents of the entire outpatient encounter rather than focusing only on the reason for visit. Supporting documentation or reportable diagnoses may be found in other places, such as radiology orders and impressions, orders for labs, anesthesia evaluations, history of present illness, physical exams performed by the physician and the final impression. Not all of these pieces of documentation will be available for every outpatient encounter, but they should be reviewed if present. Reviewing these areas will ensure that all pertinent secondary diagnosis, history and status codes are reported.

References

• ICD-10-CM Official Guidelines for Coding and Reporting
• Coding Clinic for ICD-10-CM/PCS, Third Quarter 2021 Page 32
• Coding Clinic for ICD-10-CM/PCS, Second Quarter 2022 Page: 30
• Coding Clinic for ICD-10-CM/PCS, Third Quarter 2019 Pages: 5-7
• Coding Clinic for ICD-10-CM/PCS, Third Quarter 2013 Pages: 27-28
• Coding Clinic for ICD-10-CM/PCS, Fourth Quarter 2012 Pages: 90-98
• Coding Clinic for ICD-10-CM/PCS, First Quarter 2017 Pages: 4-7
• Coding Clinic for ICD-10-CM/PCS, Fourth Quarter 2016 Page: 143
• Coding Clinic for ICD-10-CM/PCS, First Quarter 2014 Pages: 11-13, 17-18

For the past 30 years, HIA has been the leading provider of compliance audits, coding support services and clinical documentation audit services for hospitals, ambulatory surgery centers, physician groups and other healthcare entities. HIA offers PRN support as well as total outsource support.

The information contained in this coding advice is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.