How to Code Symptoms and Definitive Diagnoses
by Sue Prophet, RHIA, CCS
Determining when a symptom, definitive diagnosis, or both should
be coded can be challenging for coding professionals. This challenge is
complicated by the varying rules regarding the coding of symptoms versus
definitive diagnoses, according to the type of encounter and the particular
service rendered. In an era of increased focus on fraud/abuse and regulatory
compliance, it is especially important for coding professionals to understand
and properly apply official coding rules and guidelines. This article will
explore the various guidelines affecting symptom and definitive diagnosis
coding and what guidelines to apply.
Conditions Integral to Disease Process
Conditions that are integral to a disease process should not be assigned
as additional codes. This guideline applies to all healthcare settings.
For example, nausea and vomiting should not be coded in addition to gastroenteritis,
because these symptoms would be considered integral to a diagnosis of gastroenteritis.
Similarly, wheezing should not be coded in addition to a diagnosis of asthma.
Conditions that are considered integral to a disease process are not always
included in Chapter 16 of ICD-9-CM. For example, pain or stiffness in a
joint, which are found in the Musculoskeletal chapter of ICD-9-CM, would
be considered integral to a diagnosis of arthritis. Conversely, conditions
that may not be associated routinely with a disease process should be assigned
additional codes. A solid understanding of the disease process is necessary,
and it may sometimes be necessary to confer with the physician.
"Probable," "Suspected," and "Rule Out" Diagnoses
In the inpatient setting, if a diagnosis documented at the time of discharge
is qualified as "probable," "suspected," "likely," "questionable," "possible,"
or "rule out," the condition should be coded as if it existed or was established.
The basis for this guideline are the diagnostic workup, arrangements for
further workup or observation, and initial therapeutic approach that correspond
most closely with the established diagnosis.
In the outpatient setting (including physician offices), diagnoses documented
as "probable," "suspected," "questionable," or "rule out" should not be
coded as if they are established. Rather, the conditions should be coded
to the highest degree of certainty for that encounter, such as symptoms,
signs, abnormal test results, or other reason for the visit. For example,
if the physician documents "fever and cough, possible pneumonia" at the
conclusion of an emergency room visit, only the fever and cough should
be coded, because those symptoms represent the highest degree of certainty
for that encounter. However, if the physician documents "fever and cough,
possible pneumonia" on a requisition for an outpatient chest x-ray, and
the radiologist's diagnosis on the radiology report is "pneumonia," it
is appropriate to code the pneumonia, as this diagnosis represents the
highest degree of certainty for the encounter for the x-ray. Based on Coding
Clinic for ICD-9-CM 17, no. 1, it is appropriate to code based on the
physician documentation available at the time of code assignment.
Symptoms Followed by Contrasting/Comparative Diagnoses
When selecting the principal diagnosis in the inpatient setting, if a symptom
is followed by contrasting/comparative diagnoses, the symptom code should
be sequenced first and all of the contrasting/comparative diagnoses should
be coded as suspected conditions per the guideline mentioned above concerning
the coding of "suspected" inpatient diagnoses. For contrasting/comparative
diagnoses involving secondary diagnoses in the inpatient setting, only
the symptom should be coded. The contrasting/comparative diagnoses should
not be coded. However, when a symptom is followed by contrasting/comparative
diagnoses in an outpatient setting, only the symptom should be coded.
Symptom Versus Malignancy as Principal Diagnosis
Symptoms, signs, and ill-defined conditions listed in Chapter 16 of ICD-9-CM
that are characteristic of, or associated with, an existing primary or
secondary-site malignancy can not be used to replace the malignancy as
principal diagnosis, regardless of the number of admissions or encounters
for treatment and care of the neoplasm.
Specific Outpatient Coding Guidelines
These guidelines should be applied for facility-based outpatient services
and physician offices. As stated in the Diagnostic Coding and Reporting
Guidelines for Outpatient Services, codes that describe symptoms and
signs, as opposed to diagnoses, are acceptable for reporting purposes when
an established diagnosis has not been confirmed by the physician. However,
this means that when a definitive diagnosis has been established for that
encounter, the established diagnosis should be coded. In this case, those
signs or symptoms that are integral to the established diagnosis should
not be coded. Any conditions, including signs and symptoms, that are not
routinely associated with the definitive diagnosis should be assigned as
Encounters for Diagnostic Services
For patients receiving diagnostic services only during an outpatient encounter,
sequence first the diagnosis, condition, problem, or other reason for the
encounter shown in the medical record to be chiefly responsible for the
outpatient services provided during the encounter/visit. This guideline
must be used in conjunction with all other applicable coding rules and
guidelines. For example, it could be argued that the symptoms of "pain
and swelling in wrist" documented on the requisition for an outpatient
x-ray of the wrists are the conditions "chiefly responsible" for the outpatient
service rendered. However, the guidelines regarding the assignment of codes
for the "highest degree of certainty" and "conditions integral to the disease
process" also need to be taken into consideration. If the radiologist's
interpretation on the radiology report establishes a diagnosis of fractured
wrist, then the fracture is the condition representing the highest degree
of certainty for this encounter. The pain and swelling would not be coded,
even as secondary diagnoses, because they are an integral part of the fracture
Encounters for Ancillary Tests
Coding Clinic for ICD-9-CM 17, no. 1, clarifies that it is appropriate
for coding professionals to use physician interpretations of tests as a
basis for accurate code assignments in the outpatient setting. For example,
if the surgeon removes a lesion and the pathologist's diagnosis on the
pathology report is carcinoma, the carcinoma should be coded, as it is
the more definitive diagnosis.
This advice is consistent with the official outpatient coding guidelines,
including the guideline regarding the assignment of codes to the highest
degree of certainty for that encounter. The diagnosis documented by the
pathologist or radiologist is the condition representing the highest degree
of certainty for that visit. When the physician interpretation of a test
performed in the outpatient setting establishes a definitive diagnosis,
this definitive diagnosis should be coded and any presenting symptoms that
are integral to this diagnosis should not be coded. Any documented symptoms
or conditions that are not routinely associated with the definitive diagnosis
should be assigned additional codes. It is not necessary to code incidental
findings documented in physician interpretations of tests.
Abnormal findings in test results that are not interpreted by a physician,
such as clinical laboratory tests like CBC or urinalysis, should not be
coded unless confirmation of a definitive diagnosis is obtained from the
patient's physician. In these cases, the presenting symptoms, conditions,
or other reasons for the test should be coded.
Reason for Visit
Some payers have encouraged, or insisted, that hospitals report the presenting
symptoms for emergency room visit, even when a definitive diagnosis is
established and reporting the symptoms would violate the official coding
guideline concerning the reporting of symptoms integral to the definitive
diagnosis. The payers are requesting this information in order to establish
the emergent nature of the patient's complaint. The presenting symptoms
(such as chest pain) may justify an emergency room visit, but the definitive
diagnosis (such as hiatal hernia) is a non-urgent condition and would not,
by itself, justify a trip to the emergency room.
To solve this dilemma while maintaining data integrity and adhering
to official coding guidelines, the National Uniform Billing Committee agreed
to expand the title and definition of the admitting diagnosis field on
the UB-92 claim form to accommodate the need for information regarding
the presenting sign or symptom. The title of this data element has been
expanded to include "patient's reason for visit." The definition has been
modified to read: "the ICD-9-CM diagnosis code describing the patient's
diagnosis or reason for visit at the time of admission or outpatient registration."
For outpatient claims, this should be the ICD-9-CM code describing the
patient's stated reason for seeking care (or as stated by the patient's
representative, such as parent, legal guardian, or paramedic). The modification
of the description and definition of the Admitting Diagnosis field met
several objectives, including:
An ICD-9-CM diagnosis code should be reported in the admitting diagnosis
field on the UB-92 whenever there is an unscheduled outpatient visit to
a healthcare facility's emergency room or urgent care center. Currently,
the UB-92 claim form can only accommodate one diagnosis code to describe
the patient's primary reason for seeking care or treatment. The diagnosis
code describing the patient's reason for the unscheduled visit should only
be reported on outpatient claims. If the unscheduled visit results in an
inpatient admission, the admitting diagnosis code should be reported instead
of the reason for the outpatient visit. The use of the admitting diagnosis
field for outpatient emergent and urgent encounters became effective April
1, 2000, and applies to all payers.
facilitating claims processing by allowing providers to report the reason
the patient presented for treatment
the new outpatient definition is consistent with the intent of the prudent
layperson legislation that seeks to establish the reason the patient is
seeking care (which may differ from the diagnosis established by the physician
at the conclusion of the visit)
the outpatient definition is consistent with various national definitions
for the patient's reason for visit
providing explanation as to why certain tests may have been ordered and
reducing administrative burden on providers and payers by eliminating requests
for additional documentation in some cases
promoting adherence to established national coding guidelines
Note: Information in Coding Clinic for ICD-9-CM 17, no.
1, regarding the use of physician interpretations of tests in correct code
assignment applies only to outpatient encounters. Please refer to the first
quarter 2000 issue of Coding Clinic for ICD-9-CM for complete information
on coding outpatient laboratory, pathology, and radiology encounters, including
American Hospital Association. Coding Clinic for ICD-9-CM 15, no.
1. Chicago, IL: American Hospital Association, 1998.
American Hospital Association. Coding Clinic for ICD-9-CM 16,
no. 4. Chicago, IL: American Hospital Association, 1999.
American Hospital Association. Coding Clinic for ICD-9-CM 17,
no. 1. Chicago, IL: American Hospital Association, 2000.
Official ICD-9-CM Guidelines for Coding and Reporting. Available at
the National Center for Health Statistics Web site, www.cdc.gov/nchs/datawh/ftpserv/ftpicd9/ftpicd9.htm.
To subscribe to Coding Clinic or order a back issue, visit the AHA
Coding Resource Center
Sue Prophet is AHIMA's Director of Coding Policy and Compliance.
She can be reached at firstname.lastname@example.org.
Prophet, Sue. "How to Code Symptoms and Definitive Diagnoses." Journal of AHIMA 71, no.6 (2000): 68-70.