Focus on key factors to ensure accurate principal diagnosis selection

June 9, 2014

A patient presents to the ED with fever, gastroenteritis, nausea, and vomiting. After evaluation, the patient is found to be severely dehydrated and the physician admits the patient for administration of fluids. What is the principal diagnosis?

Initially, you might think it’s the gastroenteritis, but that’s something the physician could have treated at an outpatient level, says Heather Taillon, RHIA, manager of corporate coding support services at Franciscan Alliance in Greenwood, Ind.

Instead, you should select the principal diagnosis based on the reason for admission.

“A seasoned coder is going to know that dehydration is really the reason for admission and what should be listed as the principal diagnosis in this situation,” Taillon says.

Coding Clinic, First Quarter 2008, pp. 10–11, provides additional examples for selecting the appropriate principal diagnosis for ED encounters.

The UHDDS defines principal diagnosis as the condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care. That means the principal diagnosis is not always the condition that brought the patient into the hospital, Taillon says.

Going back to the ED patient, the patient presented with four symptoms/conditions: fever, gastroenteritis, nausea, and vomiting. The patient was actually admitted for dehydration, which was not one of the reasons the patient sought treatment in the ED. Ultimately, the physician admitted the patient to treat dehydration.

Physicians don’t always know what is wrong with a patient when the patient walks in the door. That’s where the “after study” part of the principal diagnosis definition comes into play, Taillon says.

For example, a patient presents to the ED with chest pains. The physician may admit the patient to rule out an acute myocardial infarction (MI). You would not automatically code MI as the principal diagnosis. You need to review the record and find out what the physician’s final diagnosis was.

The patient may have suffered an acute MI or may simply be suffering from acid reflux or a panic attack. Remember that the admitting diagnosis may not be the principal diagnosis.

Admission following outpatient surgery

From 2004 to 2010, CMS outpatient claims rose approximately 4.2% annually as the site of service shifted from inpatient to outpatient, says Andrea Clark, RHIA, CCS, CPC-H, CEO and founder of Health Revenue Assurance Associates in Plantation, Fla. As a result, the number of patients who may be admitted after an outpatient procedure may also increase.

An admission following outpatient surgery presents a tricky situation because the physician’s documentation may not clearly state the reason for the admission.

Consider this scenario: A patient undergoes a procedure that is normally performed as an outpatient, after which the patient would normally go home. Everything in the chart looks normal, but the patient is admitted to the hospital. The physician does not provide any information about why the patient is admitted. “It’s a good idea to go back and clarify that information with the physician because there very well might be a condition that necessitated admission that just didn’t get documented,” Taillon says.

The ICD-9-CM Official Guidelines for Coding and Reporting provides the following specific guidance for selecting a principal diagnosis when a patient is admitted following an outpatient surgery:

If the reason for the inpatient admission is a complication, assign the complication as the principal diagnosis.
If no complication or other condition is documented as the reason for the inpatient admission, assign the reason for the outpatient surgery as the principal diagnosis.
If the reason for the inpatient admission is another condition unrelated to the surgery, assign the unrelated condition as the principal diagnosis.

The third situation can present problems. “You don’t know if it’s a heart condition that was a complication of the procedure or if this patient was just a patient with a chronic cardiac condition that, after surgery, necessitated admission into the hospital to keep that patient on an even keel,” Taillon says.

Here’s where the query process comes into play, because you don’t want to assign a complication code if it truly, in the eyes of the physician, was not a complication to his or her care. It could be just a part of the patient’s chronic disease process, Taillon adds.

Neoplasm confusion

Assigning a principal diagnosis for a patient with a neoplasm generates plenty of questions, says Cheryl Collins, BS, RN, clinical documentation specialist at the University of Mississippi Medical Center in Jackson.

The basic rules regarding principal diagnosis selection are the same for neoplasms as any other condition.

One myth surrounding principal diagnosis and neoplasms is that neoplasms take precedence over other conditions. Not so, Collins says. “No guideline exists that the neoplasm takes precedence.”

Recognizing the focus of treatment helps the coder determine the principal diagnosis, she adds. Coding Clinic, Second Quarter 2010, p. 3, addresses sequencing for neoplasms.

In patients who have cancer or neoplastic disease, many times the cancer is causing multiple secondary conditions to occur. “Trying to determine and ferret through all of that information to come to a principal diagnosis is what makes this a somewhat challenging process,” Collins says.

Neoplasm case one

For example, a patient is admitted with hypercalcemia related to multiple myeloma. The focus of treatment for this visit is correcting the hypercalcemia. The physician does not treat the patient’s multiple myeloma and the patient is transferred to inpatient hospice. Therefore, the principal diagnosis is hypercalcemia (ICD-9-CM code 275.42).

“She was, unfortunately, a patient who had determined that she was ready for hospice and so she was even transferred to the hospice care for her multiple myeloma, but they had to get her hypercalcemia under control,” Collins says. Patients with metastatic or malignant cancers are often treated for their symptomology to provide comfort to them prior to being released to hospice. Coding Clinic, Third Quarter 2012, p. 16, walks through this specific example.

Neoplasm case two

So that’s a more simplistic case. Now let’s look at something more complicated.

A patient presents to the ED with metastatic cancer to his brain and spinal cord, pain out of control despite oral medication, and in need of daily radiation therapy to the spine.

The physician admits the patient for both IV pain medication and to receive daily radiation treatments.

The physician specifically documents that the patient can’t withstand traveling daily for outpatient radiation.

“This is a rarity that the physician specifically documented that the patient couldn’t withstand traveling daily for his outpatient radiation, so therefore, obviously, he had to be admitted as an inpatient in order to receive daily radiation as well,” Collins says.

The patient’s pain is controlled with IV pain medication converted to oral medication on day three. He completes 12 days of radiation therapy and is then discharged.

A lot is going on with this patient. He has metastatic cancer, out-of-control pain, and is receiving radiation. “So a lot of times it leaves the coder wondering, ‘What should the principal diagnosis be?’ ” Collins says.

What are the sequencing guidelines related to neoplasms, pain control, and radiation therapy? Pull up the neoplasm-related pain codes and it says you can assign code 338.3 (neoplasm related pain [acute] [chronic]) if it’s pain associated with cancer. You can assign this code regardless of whether the pain is acute or chronic, Collins says. It can be assigned as the principal diagnosis when the stated reason for the admission is documented as pain control. The underlying neoplasm should be reported as an additional diagnosis.

But 338.3 doesn’t have to be the principal diagnosis. When the reason for admission is management of the neoplasm and the pain associated with the neoplasm is also documented, you might also select 338.3 as an additional diagnosis. “Right there we’ve got guidance stating that it can be principal or it can be secondary,” Collins says.

The patient is being admitted for radiation therapy as well because he couldn’t withstand having it on an outpatient basis and traveling to the radiation center.

Look at the official coding guidelines related to radiation therapy. In this case, ICD-9-CM guidelines include sequencing guidelines stating that if the patient’s admission isn’t solely for the administration of chemotherapy, immunotherapy, or radiation therapy, you should report code V58.0 (encounter for radiation therapy) as the principal diagnosis, followed by a diagnosis for the malignancy.

“The sequencing rule trumps,” Collins says. So V58.0 is the only acceptable principal diagnosis. “I know the sequencing guidelines said ‘solely,’ and that can be confusing to the coder because in this case the patient had pain control in addition to radiation therapy.”

V58.0 maps to MS-DRG 849 (radiotherapy), which has a relative weight of 1.3396 and a length of stay of 4.6 days. Code 338.3 maps to MS-DRG 861 (signs and symptoms without MCC), which has a relative weight of 0.7010 and a length of stay of 2.7 days.

The patient actually stayed in the hospital for 12 radiation therapy treatments, so the stay was really 12 days long, Collins says. “When you look at this case and you look at the pain control versus radiation therapy, you can clearly see it makes more sense that really the reason the patient was an inpatient was for the radiation therapy.”

This case could have been coded differently if the physician had not documented that the patient could not tolerate traveling for his radiation treatments, Collins says. “If we had not known that the patient couldn’t withstand treatment as an outpatient, we may have had to lean toward the symptom or the pain if it’s the only thing listed as the reason for admission.”

In situations like this where a patient is receiving radiation therapy for an extended period of time and you don’t see that documented in the chart as one of the reasons for admission, go back and question the physician to get clarification, Collins adds.

Editor's Note: This article was originally published in the January 2014 edition of Briefings on Coding Compliance Strategies. Join Laurie Prescott, MSN, RN, CCDS, CDIP, is a CDI education specialist for HCPro in Danvers, Mass., and Lynda Starbuck, RHIA, C-CDI, AHIMA Approved ICD 10 CM/PCS Trainer, is a managing consultant in the Navigant healthcare practice, on Thursday, May 15, at 1 p.m., Eastern for a live webinar "Principal Diagnosis Selection: Essential Guidelines for ICD-10 Implementation."

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