Selecting the BEST Principal Diagnosis

Early on in our lives, our parents laid out choices surrounded by guidelines that they hoped would lead us to being able to make the best decisions.  Depending on how we truly understood our choices, sometimes coupled with the outcome, we were able to navigate growing up to be great decision makers.  As we transition those types of early learning skills to our coding professions, the same principles apply.  We need to know and understand our choices and based on the guidelines accompanying our choices, make the best decisions for optimal outcomes.

As I respond to coding questions and review records, the one key factor that continues in every chart whether inpatient, outpatient, emergency or ancillary is principal diagnosis or first listed condition.  In order to ensure “reason for admission after study”, medical necessity and reason for the encounter is accurately reflected, we look first to the Uniform Discharge Data Set (UHDDS) guidelines.

  • Principal Diagnosis (PDX):  The circumstances of inpatient admission always govern the selection of the principal diagnosis.  Coding directives in the ICD-10 CM classification take precedence over all other guidelines.  “…that condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care.”
  • Admission follow Medical Observation/Post- Operative Observation:  Report the medical condition that led to the hospital admission, which may be different from the reason the patient was admitted to observation.
  • Admission from Out- patient Surgery:  If the reason for the inpatient admission is another condition unrelated to the surgery, assign the unrelated condition as the principal diagnosis.  If the reason is a complication, assign the complication as the principal diagnosis.
  • Abnormal Findings:  When findings are clearly outside the normal range and the physician has ordered other tests to evaluate the condition or has prescribed treatment without documenting an associated diagnosis, it is appropriate to ask the physician whether a diagnosis should be added or whether the abnormal finding should be listed in the diagnostic statement.  Incidental findings on X-rays should not be reported unless further evaluation or treatment is carried out.

The UHDDS definition of PDX does not apply to outpatient encounters.  If the physician does not identify a definite condition or problem at the conclusion of the visit or encounter, report the documented chief complaint as the reason for the encounter/visit.

Just like our parents instilled in us the way to treat others, following rules and guidelines and making good decisions, ethics is essential to coding practices.  AHIMA Standards of Ethical Coding was recently updated, reiterating that in all decisions we make as coders, we apply the highest level of accuracy according to the documentation.  Other third-party payers may follow slightly different reimbursement methods, but the accuracy of the ICD-10 CM and ICD-10-PCS and CPT/modifiers coding is always vital.  Failure to include all diagnoses or procedures documented that meet reporting criteria may result in financial loss for the health care provider.

As we adapt the value based purchasing model, moving from paying for volume to paying for value, we need to read and understand the “clinical truth” in the records, sometimes referred to as clinical indicators.  Let’s take a look at some examples:

  1. Patient is admitted with CHF and pneumonia. Patient is given IV Lasix and IV antibiotics.  Either may be sequenced as the PDX.
  2. Patient is admitted to the ICU with respiratory failure due to severe exacerbation of COPD.  A pulmonary consultant is involved.  Treatment includes IV antibiotics, steroids, oxygen, pulse oximetry, and aggressive respiratory therapy modalities.  Either may be sequenced as PDX.
  3. Patient presents with syncope.  Syncope is due to arrhythmia.  Cardiac arrhythmia is the PDX/first listed and syncope is a secondary diagnosis.
  4. Viral gastroenteritis with fever, abdominal pain, nausea, vomiting, diarrhea.  Code only viral gastroenteritis.
  5. A patient with cholecystitis was admitted to the hospital for a cholecystectomy.  Prior to surgery, the patient fell and sustained a left femur fracture.  The surgery was canceled and a hip pinning was carried out on the second day of the hospital stay.  The PDX remains cholecystitis since it was the diagnosis that occasioned the admission.
  6. A patient was discharged two days following a hysterectomy. On the second day at home, she strained lifting a small child.  She was readmitted with wound dehiscence. The wound dehiscence is the PDX.
  7. A patient is admitted with respiratory failure and a large iatrogenic pneumothorax three days following outpatient thoracentesis for malignant pleural effusion.  Iatrogenic pneumothorax is the PDX.
  8. A patient is treated in an observation unit for 16 hours with an exacerbation of COPD, then admitted as an inpatient for treatment of a pulmonary embolism discovered on chest CT.  Pulmonary embolism is the PDX.
  9. Patient is admitted following TURP as an outpatient for post- operative bleeding uncontrolled in the PACU.  The post-operative bleeding is the PDX.
  10. Patient is being observed for 24 hours following lumbar kyphoplasty develops rapid atrial fibrillation requiring admission; atrial fibrillation is the PDX.
  11. An elderly patient with chronic cholecystitis is admitted for 3 days following an uncomplicated elective laparoscopic cholecystectomy without further explanation before being transferred to a SNF.  Chronic cholecystitis is the PDX.
  12. A patient is admitted with right lower abdominal pain. Abdominal x-ray on admission indicates an ileus pattern. The patient has intravenous fluids, multiple tests   and the discharge diagnosis is given as RLQ pain, unknown etiology.  We should query for whether the ileus pattern identified on the abdominal x-ray is possibly the cause of the RLQ abdominal pain.  When a condition is introduced and not ruled out by the documentation, we should query for any possible relationship.
  13. A patient is admitted with fever, cough and treated with antibiotics and steroids.  The diagnostic statement is COPD exacerbation and pneumonia.  Using Coding Clinic guidelines, the PDX is the COPD exacerbation followed by the pneumonia.

We have navigated through several scenarios today regarding selection of the PDX/first listed condition that I hope you find validation in your current practices or understand better the correct method of PDX/first listed selection.

References: UHDDS guidelines referenced via www.CMS.gov, and Pinson, R.D.,MD, Tang, C.L. “2017 CDI Pocket Guide”, ACDIS, and AHA Coding Clinic.

About the Author

Marie Thomas holds a Masters Healthcare Administration from Pfeiffer University, Charlotte, NC, and a Bachelor of Science in Healthcare Administration from Pfeiffer University. Marie has furthered her career education by becoming an AHIMA-Approved ICD-10-CM/PCS Trainer and Ambassador as well as earning the RHIT, CCS, CCDS, and CPC-H credentials. For more information please email us at contact@eclathealth.com