Guest Post: Offer physicians an educational overview of coding requirements for principal diagnosis

by Robert S. Gold, MD

The reason for assignment of a certain principal diagnosis is occasionally incomprehensible. First, consider what a principal diagnosis is. It’s the condition or group of conditions that, after workup, the physician determines led to the patient requiring inpatient hospital care. Essentially, it’s why the patient is in the hospital. Sometimes it’s the same as what got him or her off the couch, but not always.

Here’s one example: A patient may come to the ED for a crushed finger after dropping something heavy on it. But when the physician works up the patient in the ED, he or she may determine that the patient dropped the heavy thing because of weakness caused by a stroke.

The stroke is what needed inpatient care—the finger could have been taken care of in the ED.

Or consider the following: A patient is admitted with acute renal failure with rhabdomyolysis and a potassium level of 6.8. The folks in the ED work with the physician on treating the patient urgently with Kayexalate, insulin, and glucose. Soon after, the physician learns that the acute renal failure actually represented an organ failure from the patient’s severe pneumonia that he or she could not see on the admitting chest film because of the extent of dehydration. The physician and the infectious disease consultant agree that the patient was septic due to the pneumonia with acute tubular necrosis causing the acute renal failure.

When coding this scenario, coders will assign this case to the category (i.e., DRG) of sepsis. The principal diagnosis code will be septicemia, followed by pneumonia and acute renal failure and a code for severe sepsis. Why? Because those are the coding rules. Coders can’t deviate from certain priorities for sequencing of disease codes. And hang the fact that the physician never called it “septicemia.”

Another situation that could be confounding is the admission of a patient who has cancer. Take a patient who is severely anemic and weak; this presentation leads the physician to admit and work the patient up and administer a few units of packed cells so that he or she would feel stronger. Well, if the patient does okay and is discharged, then coders will report anemia as the principal diagnosis. Hopefully, the physician will specify whether that anemia was due to chronic blood loss from the cecal neoplasm or chemotherapy that the patient had been receiving or whatever the physician determines the cause of the anemia to be.

Consider also that if the patient dies of terminal cancer, the principal diagnosis might be the cancer. However, consider if that same cancer patient is stabalized and is about to be discharged but has an acute ST-elevation myocardial infarction (MI) which puts him or her into cardiogenic shock. The physician uses a balloon pump and discusses with the patient’s family the decision to let him or her pass away according to the patient’s wishes. The patient then dies of the acute MI. But the principal diagnosis will not be the acute MI, even though it may have been the cause of death.

See how it’s not so simple? Sometimes the rules don’t make a lot of logical sense, but they are the rules.

Editor’s Note: This post is an excerpt from JustCoding.com premium content.