Cardiology Coding Alert

Correct Usage of Fourth and/or Fifth Digit Key to Cutting Claim Denials

Of the nine diagnostic codes most rejected by Medicare for lack of specificity, four of them are cardiac codes. So, to avoid claim rejections labeled as unprocessable, experts advise that you not truncate these codes:

401.x, essential hypertension

414.xx, other forms of chronic ischemic heart disease

440.2x, atherosclerosis of native arteries of extremities

786.5x, chest pains

Even though Medicare has been routinely rejecting claims with truncated diagnostic codes (including those for cardiology) since July 1996, some cardiology coders are still not coding to the highest level of specificity, explains Susan Garrison, CPC, CPC-H, MPC, CPAR, MCS, president of Hyatt, Imler, Ott and Blont, a coding and reimbursement firm in Atlanta.

Or, they may be assigning a fifth digit inaccurately, adds Sue Prophet, RRA, CCS, director of classification and coding for The Society for Clinical Coding in Chicago, citing the ICD-9 basic coding guidelines for outpatient and physician services that state one should code to the highest degree of certainty for each encounter.

Some coders mistakenly think this means that all diagnostic codes must have five digits, and thus they add a decimal and one or two zeros, she says.

Either way, Medicare and many other third-party payers consider such incomplete or inaccurate codes invalid, which result in additional denials, correspondence and delays, Garrison points out.

So here are eight tips to help you ensure you are optimally utilizing fifth digit diagnostic coding, which will enable your cardiology claims to be processed faster and cut the number of denials.

1. More digits; more detail. ICD-9-CM contains codes with either three, four, or five digits. Most three digit codes serve as headings for broad categories which need to be further divided. The fourth and fifth digits provide more detail about the nature of the disease or condition.

Categories are subdivided by adding a decimal point as well as a fourth and/or fifth digit. Codes with fourth digits are called subcategory codes; those with fifth digits are subclassifications.
For example,

401.x (essential hypertension) always requires a fourth digit to identify the type of hypertension.

414.xx (other forms of chronic ischemic heart disease) always requires a fifth digit to determine site of ischemia.

440.2x (atherosclerosis of native arteries of extremities) always requires a fifth digit to determine type of atherosclerosis.

786.5x (chest pain) always requires a fifth digit to identify site of pain.

Note: Although a cardiologist wouldnt list 250.0x (diabetes mellitus without mention of complication) as a primary diagnosis, he or she might use it as a secondary or tertiary diagnosis. If you do, remember it requires a fifth digit to identify the type of diabetes.

2. Use three-digit codes sparingly. Use a three digit diagnostic code only when no fourth or fifth digit is available. In fact, out of the hundreds of diagnostic entries, only about 100, three-digit codes are valid without any further specificity. Of these, only a handful would ever be used in a cardiology coding, including:

393, chronic rheumatic pericarditis;

412, old myocardial infarction;

430, subarachnoid hemorrhage;

431, intracerebral hemorrhage; and

436, acute, but ill-defined, cerebrovascular disease.

3. Remember the rule. If a fourth or fifth digit is available, use it. If you dont, the code is invalid.

Dont, however, create one by adding a decimal point and zeros! Ive seen situations where the appropriate code was 412 (old myocardial infarction), which is a three-digit code that stands alone. But because the coder thought there must always be five digits, the diagnostic code was listed as 412.00. There is simply no such code, says Prophet.

4. Select diagnostic coding books carefully. Garrison reminds coders that they need an up-to-date ICD-9 coding manual. Believe it or not, some people think its not necessary to buy it yearly, she says.

She also prefers one that is color coded or uses symbols to indicate codes that require a fourth and/or fifth digit. Use a code book that is clearly flagged both in the tabular section and index [for fourth and fifth digits] to ensure coding accuracy, Garrison adds.

5. Use coding books accurately. Remember, index entries often do not contain fifth digits, Garrison explains. Thats why you need to confirm the code you find in the index by looking it up in the tabular section. Dont depend on the index to select your code; youre inviting trouble, she warns.

Prophet also reminds coders to search thoroughly. Your coding book may have a symbol, but it can still be easy to miss the fact that you need to add a fourth or fifth digit. Depending on the length of the category, the subclassification may be listed two or more pages after the start of the listing, she explains.

6. Watch for dump codes. In your quest to code to the highest level of specificity, be careful. You may go from bad to worse by assigning a dump code. These catchall codes are frowned upon by Medicare and other payers, because they are nonspecific or ill defined and should only be used after youve checked all other options, Garrison advises. (See the loosely inserted page in this issue for a complete list of dump codes for cardiovascular disease. If your issue does not have an insert call 800/508-2582.)

Here are several examples of cardiology dump codes:

Adding a fourth digit to 401.x (essential hypertension) you could select 401.9 (essential hypertension, unspecified) which is a dump code. A better choice would be 401.0 (essential hypertension, malignant) or 401.1 (essential hypertension, benign).

Dont make the same mistake when coding 414.xx (other forms of chronic ischemic heart disease) to its highest level of specificity. For example, 414.00 is an unspecified type of vessel, native or graft or other form of chronic ischemic heart disease. Likewise, 414.9 is unspecified chronic ischemic heart disease.

Tip: 414.18 (other specified forms of chronic ischemic heart disease) is also considered a dump code.

Subcategory 440.2 (atherosclerosis of native arteries of extremities), which needs a fifth digit, is also subject to becoming a catchall subclassification of 440.20 (unspecified atherosclerosis of the extremities) or 440.29 (atherosclerosis of native arteries of the extremities, other).

Finally, watch out for the symptom code for chest pains (786.5x), which needs a fifth digit. Adding a fifth digit of 0 or 9 creates these dump codes: 786.50 (chest pain unspecified) and 786.59 (chest pain, other).

If you discover you are about to assign a dump code, go back to the medical record and look for definitive information, Garrison says. If you cant find it there, ask the physician to clarify. (But code only what is actually documented in the chart, she recommends.)

A dump code should only be used when it most closely fits the diagnosis, she stresses. Dont just get in the habit of automatically assigning them.

7. Update your encounter forms. If your encounter form or superbill only lists three-digit categories, rather than listing the fourth and fifth digit subcategories and subclassifications, then the cardiologist may truncate the code inadvertently.

Ive seen this in quite a few practices, Garrison notes. They are using the encounter form as a coding book: the coder or biller automatically transfers the incorrect three-digit code to the claim form, and that results in an automatic rejection.

Garrison also recommends checking your cardiology practices superbill or encounter form to make sure it clearly indicates which codes are dump codes.

8. All symptom codes need five digits. Coding to the highest degree of certainty means coding only what you know as fact. Yet, cardiologists often see patients for ill-defined symptoms that require further testing. Until the results are in, however, only symptom codes should be used (including categories 780 to 789). These codes, which serve as a provisional diagnosis, always require a fifth digit, Prophet points out.

For example, use symptom code 786.5x (chest pain) when the cardiologists does not yet know the condition which is causing the pain. For this code, you should always use the fifth digit to identify site of pain, Prophet says.

Tip: Remember, whenever possible, to avoid the dump codes 786.50 and 786.59.

However, if the physician concludes, during the encounter what the exact diagnosis is, such as unstable angina (411.1), he or she should use the actual diagnosis code rather than the symptoms codes.