Basics of ICD-9 Coding
By Emily Hill, PA-C
Accurate ICD-9 coding helps ensure payment, and avoids any hint of fraud or
Submitting claims to third-party payors and documenting the care given to each
patient is a fact of life in health care today. All medical procedures, supplies
and diagnoses are identified by codes.
Current procedural terminology (CPT) coding is designed to numerically
identify the cognitive, procedural and material services provided to
the patient. International
Classification of Disease, Ninth Edition (ICD-9) coding is the system of numerically
identifying the disease or physical state that justifies the performance or
provision of those services or procedures. In other words, CPT codes are "what
you do" and ICD-9 codes are "why you do it." Practitioners must
document and code both for each patient. Because reimbursement from third-party
payors is largely dependent on the coding selection submitted by the physician,
coding accurately is key to getting proper payment for services and avoiding
allegations of fraud and abuse.
This month, we will look at the basics of ICD-9 coding. In future issues, we
will explore the nuances of CPT coding to ensure that the services reported
are accurate and allow for appropriate reimbursement.
What Are ICD-9 Codes?
ICD-9 codes are three-, four- and five-digit codes that describe the diagnosis,
symptom, complaint, condition or problem for which a physician sees a patient.
These codes are also used to indicate other reasons why a person has sought
medical care, such as a routine health examination. The codes are set up to
be specific; each digit gives important information about a patient. If the
diagnosis can be defined by five digits instead of three or four, all five
must be used. Many payors, including Medicare, do not pay for services unless
the diagnosis has been carried to the highest number of digits.
When seeing a patient for monitoring and treatment of classical migraines,
this descriptor alone would lead a physician to report the ICD-9 code as 346.0.
However, it is possible to code to the fifth digit under this category. The
fourth digit describes the particular type of migraine, while the fifth indicates
whether or not the headaches are intractable. In this example, failure to use
the maximum number of digits available in the category will result in denied
payment for the office visit. To be sure the highest number is used, look over
the codes in that category.
Why Are ICD-9 Codes Needed?
Although the actual payment amount is linked to the CPT code, a proper
diagnosis is needed to show why a service was necessary. Each service
a line item (CPT code) on an insurance claim form, and an ICD-9 code must be
linked to it to establish the "medical necessity" of the service.
Establishing "medical necessity" basically means justifying choice
of treatment by linking the service (CPT code) to the diagnosis, symptom or
For example, the patient who presents for her regular visit for monitoring
of migraine headaches also complains of chest pain. As part of the first step
in the workup, an electrocardiogram (ECG) is done in the office. On the claim
form, however, the only diagnosis listed is migraines. The insurer will most
likely not pay for the ECG because the medical need for the test is not clear.
Linking the specific symptom of chest pain or angina to the ECG will indicate
why the test was ordered.
If a Patient Only Has Symptoms, What Should Be Coded?
Code just the facts. Patients are often seen for ill-defined complaints,
such as "chest pain" or "numbness." A specific condition may
be suspected, and appropriate diagnostic tests ordered; however, until the
results are known or until a definitive diagnosis is made, only the symptom
should be coded. There are no codes for words like "suspected" or "probable";
labeling patients with a disease without certainty should be avoided.
What If There Are Several Facts Or Diagnoses for a Patient?
Prioritize. When more than one diagnosis applies to a patient,
code the primary diagnosis first, followed by the second most important,
etc. Rank diagnoses so that the one listed as primary is the one receiving
the most emphasis at that encounter. There is no reason to code a diagnosis
that does not affect patient care.
Up to four diagnoses can be submitted on each claim form and linked to each
service. Make sure that an appropriate diagnostic code is specifically linked
to each CPT code to show that the service is appropriate and medically necessary.
Remember, some payors will read only the first diagnosis linked to an individual
CPT code when processing the claim. It is therefore important that the prioritizing
and linking of diagnostic codes are done accurately.
Coding appropriately can streamline the payment process from third-party
payors. Even in managed-care environments, accurately identifying the
are treated is important for practice profiling and contract negotiations.
In addition, a review of the reasons patients come into the physicians
office often provides valuable management information. Although the coding
process may seem confusing at first, it is an important time-saving and management
Emily Hill, PA-C is President of Hill & Associates, a
national health-care consulting firm specializing in coding and compliance
for physician practices. Her e-mail address is Emily@codingandcompliance.com.