Ophthalmology Management

Taking the Mystery Out of ICD-9 Coding
Here's a short course on the logic behind these diagnosis codes and how to use them properly to support your claim for reimbursement.
By Kevin J. Corcoran, C.O.E., C.P.C., F.N.A.O., San Bernardino, Calif.

W hen discussing proper coding, most people are preoccupied with current procedural terminology (CPT) codes. After all, CPT codes have monetary value attached to them and are most important to the bottom line. However, you can't view CPT codes in a vacuum. Your diagnosis must support the legitimacy of the code.

The other important aspect of a claim is the proper use of diagnosis codes or Inter-national Classification of Diseases - 9th Revision Clinical Modification (ICD-9-CM or ICD-9) codes. The original intent of these codes was to track mortality and epidemics. In this age of computerization and electronic billing, ICD-9 has evolved into an efficient way to justify the medical necessity for your claim.

Diagnosis Code Vignettes

Here are three hypothetical cases. Would your office have coded them properly?

1. A patient presents with sudden-onset, severe pain in and around the right eye. His vision is cloudy, and he's nauseated. His intraocular pressure (IOP) is 55 mm Hg and you note corneal edema, shallow anterior chamber and occluded angle of the right eye. You begin treatment and plan a laser peripheral iridotomy (LPI) once the cornea clears. Of the seven angle-related glaucoma codes, the most appropriate in this situation is 365.22 -- Angle-closure glaucoma.

2. The same patient returns to your office 1 week later for prophylactic LPI in the fellow eye. The most appropriate glaucoma code here is: 365. 02 -- Anatomical narrow angle.

3. A patient presents for a diurnal curve. Cup-to-disc ratios of each eye are greater than 0.6 but IOPs are in the mid-teens. Scanning laser ophthalmoscopy revealed optic disc abnormalities consistent with glaucoma. The glaucoma specialist wishes to determine target pressure before beginning medical therapy. The most appropriate diagnosis code for the serial tonometry is: 365.12 -- Low-tension glaucoma.


	Scanning laser ophthalmoscopy detected optic disc abnormalities in case #3.

The code you choose for your primary diagnosis must be consistent with the reason for the patient's visit or his chief complaint, which may not be the most serious disease in his history. Remember, the diagnosis code provides the justification or medical necessity for the procedure, so make it as specific as possible.

Start by looking for the disease or condition in the alphabetical listing, Volume 2, then note the ICD-9 code. Next, locate that number in the tabular data in Volume 1. If the diagnosis listed is non-specific, you'll need more information. If multiple codes are required to justify the services rendered, list them in order of importance with the most significant first. Be aware that some third party payers, including Medicare, truncate the list and look only at the first diagnosis, so make it count!

The usage and organization of terms in ICD-9 can be confusing for anyone unfamiliar with these reference works. For example, for a patient with ocular hypertension, your first instinct might be to go to "O" for ocular. But, because the book is organized by diseases, conditions and symptoms, "hypertension" is a better first choice than the anatomical term.

The tabular list is arranged as a series of topics with indented categories and subcategories, much like a traditional outline. For example, 365 is the global three-digit number for glaucoma. On the next line and indented is 365.0 borderline glaucoma. On the following lines and indented further are five-digit codes, beginning with 365.00 preglaucoma, unspecified. You must select the code that's indented furthest because the shorter codes are merely titles for organizational purposes. So, 365 or 365.0 are unsuitable and will cause claims to fail.

Medicare policy echoes these instructions: "Codes must be used to their highest level of specificity; this may include some three-digit codes. If diagnoses are coded to the highest level, using the same database for all bills and requests for payment will permit meaningful trend analysis and data comparisons." You'll find 44 glaucoma codes in the ICD-9 book, illustrating how detailed the diagnosis can be.

In Volume 2, where the diagnoses are alphabetical, italicized brackets ( [ ] ) indicate that two diagnoses are required, one for the etiology and the second, in the slanted brackets, for the manifestation. For example, a diagnosis of phacolytic glaucoma and hypermature cataract will appear in the ICD-9 book as: Glaucoma, phacolytic, with hypermature cataract 366.18 [365.51].

Accuracy is paramount. You don't want to claim that a patient has a disease when, in fact, he does not. Consequently, never use a "rule-out" or "resolved" diagnosis. Usually, this isn't a problem with glaucoma because "suspect" codes let you apply subclinical disease to a patient. However, the patient must have a finding that makes him a suspect, such as asymmetric discs. Without symptoms or findings, the most appropriate choice is a V code.

Some patients have legitimate reasons to be seen by an ophthalmologist, even though they don't manifest symptoms. An example is an asymptomatic patient referred by an optometrist who obtained abnormal intraocular pressures (IOP) with a pneumotonometer and suspects glaucoma. If the ophthalmologist doesn't find elevated IOPs using applanation tonometry and suspects that the initial measurements were wrong, the appropriate code is V71.89, observation and evaluation for specified suspected condition not found.

Alternately, if a patient requests an evaluation for possible glaucoma because she's aware of a family history of this disease, you'd use code V80.1, special screening for glaucoma. Be aware that some of the V-codes, such as V72.0 "routine exam of eyes and vision," indicate that your charge is for routine or screening purposes and might not be covered by a third party payer.

You'd think being familiar with the ICD-9 manual and understanding the nuances would be enough to file claims properly. However, many payers employ commercial software to find code pairs that don't belong together. These are often called "black-box edits."

Although valuable to payers, this program is frustrating to providers. The edits are not published, and payers are not forthcoming with information when asked. Therefore, when a claim is denied your billing clerk may not know why and can't find out.

Understanding ICD-9-CM is as important to proper claim submission as CPT. It can mean the difference between getting paid or not. Keep these three basic rules in mind:

2. Be as specific as possible by applying fourth and fifth digits whenever you can.

3. Check that your ICD-9 code is consistent with CPT rules. For example, if you use a separate procedure code, then identify an additional diagnosis to justify that service.

By gaining proficiency, you'll save time and money on third party billing and prevent ac-counts receivable from increasing needlessly.

ICD-9 Coding Do's and Don'ts

Be as specific as possible and consistent with the patient's medical record. Using nonspecific codes may not reveal adequate medical necessity for the service.

Code symptoms if you can't make a definitive diagnosis.
Document whether a condition is chronic or acute and the planned treatment. For an acute condition in an emergency situation, be sure to identify the nature of the condition. A chronic disease can be listed for multiple visits as long as you continue to treat it.
Identify how injuries occurred.
Understand the third party payer guidelines. Some payers truncate the diagnosis list and ignore the second or third ICD-9 code.
List chronic conditions or secondary diagnoses only if they pertain to that particular visit.
Make certain your fee slip is relevant for the patient population of your practice. For example, if your practice is primarily cataract, you don't need to list all the strabismus codes.
Review the fee slip and coding manuals with your staff and make sure the fee slip is accurate and easy to use.
Have a central coding area that includes the necessary manuals for proper coding: CPT, ICD-9, and HCPCS manuals, as well as dictionaries and other references. Buy new manuals to replace obsolete editions.

DON'T

Use a diagnosis code that's no longer applicable. Instead, use a history of the disease (i.e., V-codes).
Code only from the alphabetical listing in Volume 2. Volume 1 shows exclusions, inclusions and notes to ensure that the code chosen best matches the physician's diagnostic assessment.
Use a "rule out" diagnosis. If the physician searched for pathology but didn't find it, then the exam was "screening" the patient for a suspected disease. Don't describe the patient with a disease or condition he doesn't have.