Professional Coding: Part Two. Clinical Coding: ICD-9

This is the second of a three part series on clinical coding. The first article focused on CPT coding. In that article, I discussed the origin of CPT codes as being owned and copyrighted by the American Medical Association and how they are used to describe medical, surgical, and medically related procedures. In this article, I will direct attention to the International Classification of Diseases (ICD), 9th Edition.

The ICD series of codes was established approximately 400 years ago by physicians in Europe. These codes were useful in categorizing disease symptoms and assisting in diagnoses during a time when medical science was more an art than a science. The ICD code series currently belongs to the World Health Organization and is used, still, to group and classify diseases. On a worldwide basis, the diagnostic classification of diseases provides a basis for tracking and monitoring outbreaks, progressions and regressions of disease processes in various regions.

As practitioners, we sometimes view these codes from the restrictive perspective of reimbursement only. However, in the United States, the ICD code series is used in combination with the CPT code series to establish a common language of diseases and for tracking treatments and procedures for statistical analysis, for the determination of incidence and prevalence of disease and trauma, for utilization of services analysis, and of course, for reimbursement and cost analysis reasons.

Through the early and mid 1980's, diagnostic procedures and diagnoses were both described in narrative terms. The narrative terms had no commonality or universality and varied dramatically across professionals who used them. Although both CPT and ICD codes existed during those years (and earlier), their common use was not adopted until the mid to late 1980's when much attention was given to discovering how much it costs to practice medicine. As a result of increasing costs, changes in health care delivery models, interest on the part of Congress (due to the cost of Medicare and Medicaid), all parties recognized the need for a common language to describe, and allow analysis of, what was done and what was found. Hence, the formal adoption of the diagnostic codes of the ICD system.

The ICD-9-CM actually contains two sets of codes. The first part of this discussion will focus on the diagnostic codes. The second part of this discussion will direct attention to the "V" codes which are often confused with CPT codes.

Diagnosis codes are composed of three to five digit identifiers intended to describe a disease entity with significant precision. Beyond reimbursement issues, these codes unify the language of diseases among professionals, government entities, third party payers, and statisticians.

For example, let's look at the diagnosis of conductive hearing loss. Under the simple heading of "conductive hearing loss", the implication is made that a mechanical problem exists impeding the entry of sound into the cochlea. However, from a clinical perspective, there are various types of conductive hearing losses; disarticulation, perforation, impacted cerumen, otosclerosis etc. They may arise from the middle ear, from the ear canal region, or both. A conductive hearing loss may also be combined with a sensorineural hearing loss to produce a mixed hearing loss.

Rather than relying on one's verbal description, the numerical designator specifies the region of involvement of conductive hearing loss in a manner that is much more precise and can be tracked statistically. In an example of conductive hearing loss of middle ear origin, the designator of "389" specifies hearing loss and the suffix ".03" specifies middle ear origin. Hence the complete code "389.03" describes hearing loss of middle ear origin.

In like manner, "sensorineural hearing loss" also comes from the "389" (hearing loss) family of codes. The suffix ".1" specifies the broad category of sensorineural hearing loss. Hence the appropriate diagnosis code for generic sensorineural hearing loss is "389.1". But one could be more specific if you knew for sure that the loss was strictly sensory in nature. Then the diagnosis code would be 389.11. If the loss were strictly neural in nature, then the code would be 389.12. Nonetheless, since our diagnostic tools do not let us differentiate sensory from neural very often, we typically use the code 389.1 which literally means, "sensorineural hearing loss, unspecified."

Neural hearing loss of central origin carries this example one step further. One would still use a code from the "389" family and the suffix ".14" to identify the symptoms as involving the neural system or central origin. Therefore, the diagnosis code for central auditory processing disorder or central (cortical) hearing loss could be "389.14".

The Medicare standard of diagnosis coding specifies that a professional will provide a diagnosis code to the "highest possible level" which means that we will use more than the three-digit designator (i.e., 389: hearing loss). We are required to use the greatest specificity possible to designate the type of hearing loss or the anatomical region of involvement for abnormal auditory function. Most often this means using 389.1 for sensorineural problems, 389.03 for conductive hearing losses of middle ear origin, 389.01 for conductive hearing losses involving the external auditory canal (i.e., aural atresia), or 389.2 for mixed (conductive and sensorineural) hearing losses.

The question often arises, "What code do I use when I don't know what kind of hearing loss a child has? I only know that the child probably has hearing loss." An allowance is made for this situation in that the code "389.9" means "hearing loss, unspecified." Once hearing loss is confirmed and the type of hearing loss is known (i.e., conductive or sensorineural), then the diagnosis code can be changed to reflect with greater precision what type of hearing loss is being described.

Another common question is, "What diagnosis code do I use then the hearing evaluation turns out to be normal?" Many clinicians have attempted to use the code, "V72.1" (hearing test) for lack of a better code. Unfortunately, they are often not reimbursed when using that code.
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See Author's Note Below

AUTHOR's NOTE: There are two issues. First, there is no code for normal hearing. One must use a hearing code somewhere in the 389 family of diagnosis codes. Attempts to use V72.1 are not appropriate as it is not a diagnosis of normal hearing, it is a designation of a procedure that was done and was not medically necessary relative to the primary purpose of the patient's visit. Secondly, "normal hearing" is a range and not an absolute value. There are occasions when one's thresholds are still within the general range of "normal" but are not as good as they should be due to an entity like otitis media. In that case, many audiologists use the term, "slight hearing loss" to designate that the drop in hearing thresholds is not great, but the thresholds are not where they should be. Audiologists must use a diagnosis code that matches who they are and what they have done. If a hearing evaluation procedure was done, the diagnosis code must be in the hearing family of codes. Generally, it is not within the realm of audiologists to diagnose "otitis media" despite a slight drop in hearing sensitivity and flat tympanograms, because there are other entities besides otitis media that can produce that same pattern of results. Therefore, we must use a code that deals with some element of physiology and location. For otitis media, even with thresholds still within normal range, I submit that the appropriate ICD-9-CM code would be 389.03 on the basis that it reflects abnormal mechanics of the middle ear.

If the patient has a history of otitis media and currently has totally normal findings, then I believe the correct diagnosis would be 389.9, hearing loss; unspecified. As stated above, there is no code for "normal" in the ICD-9 book. Therefore, following the precedence of medicine, the coding model is to use the code for the primary complaint or symptom and the ".9" suffix for unspecified.

The reader is urged to seek the advice of their own billing and reimbursement experts, the American Medical Association, Medicare, Medicaid, the private and commerical insurance companies they work with, and other authoritative sources for their interpretation and guidance on these issues.
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Medicine, in general, has wrestled with this dilemma for years. Simply, one is not allowed to be "normal" in the ICD coding system. This system assumes that one is seen in the health care system because of illness (real or perceived) or is displaying symptoms that may require medical evaluation and intervention. The generic standard that the field of medicine has adopted is to list the diagnosis code from the family of codes describing the primary symptom and then to use the suffix ".9" , indicating unspecified.

Under this circumstance, an adult being evaluated for possible hearing loss or a child receiving a follow-up audiological for otitis media would receive a diagnosis of 389.9 (hearing loss, unspecified) if, indeed, the diagnostic findings were normal. Another critically important point is that the diagnosis code must match the discipline rendering the diagnosis. This means that if an audiologist receives a child for hearing evaluation with the presenting diagnosis of "status post-meningitis", the primary diagnosis used by the audiologist MUST NOT be "status post-meningitis". The primary diagnosis must be a hearing or balance related diagnosis consistent with our discipline and our scope of practice. A secondary diagnosis could be the meningitis code, but we get paid and are tracked for service utilization based on the primary diagnosis.

Moreover, a patient is referred to the audiologist for a consultation. Of course, it is not within our scope of practice, using the meningitis example (above), to affirm that the child really had meningitis. In this case, our primary purpose is to determine if the child had hearing loss associated with the meningitis. A similar point is made for the patient referred with the diagnosis of acoustic neuroma. Again, it is beyond our scope of practice to diagnose an acoustic neuroma. However, it is within our scope of practice to diagnose the presence of abnormal auditory function and to specify the anatomical region(s) of origin for the hearing loss (middle ear, cochlea, retrocochlear, etc.). Consequently, the diagnosis codes we use must match our professional identity.

The remaining portion of this article is devoted to the use of "V" codes. Please note, ICD-9-CM "V" codes must not be confused with the "V" codes used by Medicaid and Medicare. "V" codes used by Medicare and Medicaid will be discussed in the third article in this series.

The "V" codes listed in the ICD-9-CM manual are part of a supplemental code section of specific procedures. The most commonly used code for audiologists in this series is "V72.1" (hearing evaluation). These codes are used when a procedure is done that is unrelated to the primary purpose of a physician visit. For example, if a patient came to a physician for the purpose of monitoring high blood pressure and requested a hearing test while he was there, V72.1 would be the code used to reflect that this was a service rendered apart from the primary reason for the patient visit. As such, it is often considered "not medically necessary" by third party payers and, therefore, non-reimbursable. This code would be appropriate for use in public school screenings where the service should be documented with the realization that insurance companies will not reimburse. In contrast, this code would not be appropriate for use with a patient who was referred out of concern for possible hearing loss, but who indeed had normal auditory function. Following the example of medicine, the diagnosis code 389.9 would be more appropriate in that situation.

My summary for both the CPT coding system and the ICD-9-CM system is that we must describe numerically what we did and what we found. There will be occasions when we will not find a code which describes exactly what we did or what we found. In those instances, we must come "as close to truth as possible" remembering that these codes comprise a common language that is sometimes not sufficient in each and every situation.

The other caution is the use of "home-made" codes. These sometimes are created by hospitals and other large health care settings. In those instances, the descriptor of the code may be abbreviated or changed to reflect common usage for that facility. To alleviate that possibility, I encourage all professionals to purchase or arrange access to CPT-4 and ICD-9-CM manuals. The CPT-4 manual can be purchased from medical book stores or from the American Medical Association. The ICD-9-CM manual can be purchased from medical book stores, the American Medical Association, or can often be special ordered through Barnes and Nobel, Borders, or Amazon.com. Each manual will be a tremendous asset to help assure accuracy in procedure coding, precision in diagnosis coding, and to improve reporting and reimbursement efforts.