What Is The Difference Between Inpatient And
Outpatient Coding?
Medical coding is the first stage in the medical
billing process. It involves assigning standardized codes to diagnoses and
medical procedures. One of the main challenges for healthcare organizations is
knowing the thousands of ICD-10 codes and CPT codes as well as keeping track of
updates to report the correct codes for the services physicians provide. This
is crucial for proper patient care and reimbursement purposes and many
organizations rely on medical billing and coding
services provided by experts to ensure clean claim submission and
facilitate accurate payments. Experienced medical coders are also knowledgeable
about the differences between the codes for inpatient and outpatient visits.
Inpatient vs Outpatient Coding
To understand the differences between inpatient and
outpatient coding, it is necessary to clearly distinguish between the terms inpatient
and outpatient.
“Inpatient” means that the patient is formally
admitted to the hospital on the physician’s order. The facility where the
patient is admitted for an extended stay may be a hospital, nursing home, rehab
facility, or long-term care facility. Staying in the hospital overnight does
not necessarily make the patient an inpatient.
“Outpatient” refers to a patient who is treated but
not admitted to the hospital for an extended stay. In most cases, outpatients
are released from the hospital within 24 hours. The outpatient status remains
even if the patient stays in the facility for more than 24 hours, but the
physician has not written an order for their admission as an inpatient. For
instance, a patient who comes to the facility and is treated and undergoes
tests but is not admitted, will remain an outpatient even if they spend the
night in the hospital.
Inpatient Coding and Inpatient Coding – Key
Differences
Inpatient coding refers to the codes used for
reporting the patient’s diagnosis and procedures performed on inpatients. Both
ICD-10-CM and ICD-10-PCS coding manuals are used for inpatient coding.
ICD-10-PCS is exclusively used for inpatient, hospital settings in the U.S.
ICD-10 PCS excludes common procedures, lab tests, and educational sessions that
are not unique to the inpatient, hospital setting.
Outpatient coding uses ICD-10-CM diagnostic codes
and CPT or HCPCS codes, which specifically apply to services and supplies
provided in the outpatient setting. Documentation plays a key role in assigning
CPT and HCPCS codes.
Inpatient coding is more complex than outpatient
coding. Inpatient codes report the full range of services provided to the
patient over an extended period of time or the period of hospitalization.
Inpatient coding also comes with a present on admission (POA) reporting
requirement. Present on admission is defined as the conditions present at the
time the order for inpatient admission occurs. The aim of the POA indicator is to
distinguish conditions present at the time of admission from the complications
or conditions that develop during the patient’s stay at the hospital.
In outpatient coding, code assignment is based on
the visit or encounter. Outpatient coding applies when a patient receives
treatment but remains in a facility less than 24 hours.
Signs and symptoms reported as part of the primary
diagnosis should not be coded in inpatient settings. However, when a definitive
diagnosis is not included in the physician’s documentation, inpatient coders
may code additional signs and symptoms and suspected conditions. If a diagnosis
remains uncertain at the time of discharge, the condition should be coded as if
it existed or was established.
Many outpatient procedures do not have a definitive
diagnosis. In the outpatient setting, coders should never assign a diagnosis
code unless that diagnosis has been confirmed by diagnostic testing, or is
otherwise certain. Uncertain diagnoses are those indicated by the following
terms:
- Probable
- Suspected
- Questionable
- “Rule out”
- Differential
In the outpatient setting, it is acceptable for
coders to report the patient visit to the highest degree of certainty based on
signs, symptoms, or abnormal test results that occur at the time of the patient
encounter. However, before assigning the codes for such signs and symptoms,
coders should check with the provider for any new results and information that
can offer a definitive diagnosis.
Outpatient services are covered as part of Medicare
Part B, while inpatient services fall under Medicare Part A or hospital insurance.
Many rules and regulations govern Medicare reimbursements and the copay for
which the patient may be responsible.
Inpatient services are typically coded according to
Medicare Severity-Diagnosis Related Groups (MS-DRGs). DRGs group patients
according to diagnosis, treatment and length of hospital stay. The assignment
of a DRG depends variables such as: principal diagnosis, secondary diagnosis or
diagnoses, surgical procedures performed, comorbidities and complications,
patient’s age and sex, and discharge status. Complications and comorbidities
(CC) add to the severity and reimbursement of the episodes of care. Proper
assignment of MS-DRG requires the right tools based on ICD-10-CM and PCS codes
and guidelines.
Inpatient and outpatient coding requires professional
expertise. Partnering with a medical billing outsourcing company
that has certified and experienced coders on board can help hospitals and
practices ensure accurate code assignment, successful claim submission, and
timely and appropriate reimbursement.
