Coding Stroke for the IRF-PAI and Claim Form

Coding professionals in the inpatient rehabilitation facility setting are keenly aware of the uniqueness and challenges of coding for this level of care. In most facilities, coding is done within four days of admission for the Inpatient Rehabilitation Facility Patient Assessment Instrument (IRF-PAI). After discharge, the coding professional assigns codes for the IRF-PAI and the claim form. This article will address the coding of stroke patients for the IRF-PAI and the claim form.

The National Institute of Neurological Disorders and Stroke states that roughly 800,000 people each year suffer a stroke, with two-thirds of those receiving rehabilitation services. Stroke is the most frequent impairment group category for most inpatient rehabilitation facilities. For coding professionals, it can also be the most confusing because of the uniqueness of the category.

Etiologic Diagnosis

The Centers for Medicare and Medicaid Services (CMS) IRF-PAI manual gives instructions that the etiologic diagnosis is the problem that led to the impairment for which the patient is receiving rehabilitation. As coding professionals, we are trained and conditioned to know that coding stroke patients in a post-acute setting, we use the late effect codes, I69.xxx. But for the etiologic diagnosis, the IRF-PAI does not always follow ICD-10-CM coding guidelines. Because the etiologic diagnosis is the condition that led to the IRF admission, the code will be based on the acute condition. This means that the etiologic diagnosis for stroke is the acute stroke code assignment that was likely also used in the acute setting. As noted in the CMS manual, this should be the diagnosis for the most recent stroke if the patient has had multiple strokes prior to IRF admission.

There is a rare exception to this. The etiologic diagnosis may be the late effect code (I69.xxx) if the patient has completed an IRF stay for the most recent stroke.

Impairment Group Category

There are five impairment group categories (ICGs) for stroke. Each category refers to the laterality of the deficit and not the laterality of the stroke.

For the stroke category, the selection of the IGC depends on the presence of paresis in the patient. One point of confusion is with the laterality of the cerebrovascular accident (CVA) site. Keep in mind that the IGC is selected based on the presence and laterality of the weakness and not the laterality of the stroke. For 01.1 Left body involvement, this is a category for a patient resultant left hemiparesis from a prior stroke. IGC 01.2 would indicate a patient with right hemiparesis, and 01.3 would indicate a patient with bilateral hemiparesis. If there is no indication of paresis, the patient is assigned to 01.4 No paresis. This category is assigned even if the laterality of the stroke is documented because it is based on the weakness. The principal diagnosis for 01.4 No paresis may be the deficit receiving the most significant treatment.

The category 01.9 Other paresis is for a patient with some weakness that does not fall into hemiparesis. If the patient has monoplegia of on limb, for instance, 01.9 Other paresis is selected. The I69.xxx code reflecting the paretic condition is used for the principal diagnosis.

It is important to remember that a spontaneous or nontraumatic subdural hematoma, or a bleeding between the brain and its outermost covering, is not assigned to the stroke category. This condition is assigned to the 02.1 Nontraumatic brain injury. The information below is not pertinent to the nontraumatic brain injury category.

IRF-PAI Codes – Line 24

Stroke IGC is an area that makes coding for IRF a bit more complex. Because the IRF-PAI manual states that conditions already reflected by the impairment group category are not included in the IRF-PAI line 24 co-morbid condition list, the I69.xxx are not used for line 24. Instead, coding professionals are to assign codes on the IRF-PAI for the stroke deficiencies being treated. For instance, a stroke patient being treated for apraxia is assigned R48.2 on the IRF-PAI. On the claim form, I69.390 is used for apraxia following cerebral infarction.

Because the hemiparesis is in the IGC description, there is no additional code on the IRF-PAI for the hemiparesis. In the stroke category, there would be no I69.xxx codes on line 24 co-morbid conditions. There would also not be any acute CVA codes on line 24. The acute CVA code is only assigned to the etiologic diagnosis.

The exception would be a patient who suffers a stroke while admitted to the IRF and does not go out acute for at least two days beyond the day of diagnosis. This would be quite a rare occurrence. There is generally never a time to code an acute stroke other than the etiologic diagnosis for the stroke category. In all other IGCs, the I69.xxx late effect codes are used for patients with deficits related to stroke.

Claim Form Codes

While coding guidelines do not impact the etiologic diagnosis, ICD-10-CM coding guidelines are followed for the claim form. This is the place to use the late effect codes for a stroke category patient. The I69.xxx code and any additional codes needed per the ICD-10-CM guidelines are used. For a patient admitted to IRF in the stroke category with aphasia, the coding professional will report R47.01 Aphasia on line 24 of the IRF-PAI and I69.320 Aphasia following cerebral infarction on the UB form. Be mindful that the ICD-10-CM coding guidelines are used for the claim form. If a patient has oropharyngeal dysphagia related to a stroke, R13.12 OP Dysphagia is used on the IRF-PAI. On the claim form, I69.391 is assigned, but there is a “use additional code” note for dysphagia. R13.12 is also assigned on the claim form.

All other conditions impacting the IRF stay are reported on the claim form following coding guidelines.

Scenario

In the acute hospital, a patient arrives in the emergency department with speech disturbance and weakness in the right lower extremity. Imaging reveals an acute embolic infarct in the left posterior cerebral artery. The patient is now admitted to this IRF facility for treatment of their stroke deficiencies. The patient, who is right-handed, remains with weakness in the right lower extremity. Medical history is difficult to attain because of the patient’s dysarthria. The patient is also with paresthesia noted during physical exam. Speech therapy will assist with the patient’s oropharyngeal dysphagia. The patient’s medical history includes hypertension and chronic diastolic congestive heart failure (CHF).

Rationale

IGC, Etiologic Dx, and Principal Dx

The condition that led to the impairment being treated in the IRF stay is the cerebral infarction, I63.432. The infarction is the etiologic diagnosis even though it is no longer a reportable condition for the IRF stay under ICD-10-CM coding guidelines. The IGC is in a stroke impairment group, 01.9 Other Stroke based on the right lower extremity weakness. Because this is not a full hemiparesis, it does not fall into the 01.2 Right body stroke IGC.

Because the UB-04 claim form requires the principal diagnosis as defined by the ICD-10-CM coding guidelines, the principal diagnosis on the form is I69.341 Monoplegia of lower limb following cerebral infarction affecting right dominant side. The weakness will be the primary focus of the treatment.

Co-Morbid Conditions

Codes (from Chapter 18 – Symptoms and Signs) for the remaining infarction residuals are assigned on the IRF-PAI, because the infarction is already included in the IGC. The infarction sequelae code is used on the UB-04 form to indicate the sequelae from the infarction as instructed by the ICD-10-CM code book and guidelines. For the dysphagia, code R13.12 is used on both forms. The instructional notes in the ICD-10-CM codebook under I69.391 state to “use an additional code to identify the type of dysphagia, if known.” For stroke deficits that fall under I69.398 Other sequelae of cerebral infarction, the second code defining the deficiency (in this case paresthesia) is assigned on both the IRF-PAI and the UB form. The codes for the hypertension and diastolic CHF are the same on both forms and are not impacted by the IGC assignment for this scenario.

Tier

Code R13.12 is a tier 2 diagnosis code. The CMS list of tier diagnoses states that this code is excluded from the stroke category, so this does not affect the tier assignment. Diastolic congestive heart failure is also on the tier diagnosis list and is not excluded from the stroke category. This diagnosis code will assign tier 3 to the CMG.

Adhere to Guidance

Coding for stroke can be tricky. Keeping in mind the guidelines in the IRF-PAI manual as well as the ICD-10-CM coding guidelines will assist in having accurate code assignments.

John Barrilleaux (john.barrilleaux@gmail.com) is an assistant professor and interim program director at Southern University at New Orleans. He is also principal consultant and president of Rehab Coding Services LLC.

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