Home Health ICD-9/ICD-10 Alert

Avoid 'other specified' codes for unspecified diagnoses.

Knowing the difference between NOS and NEC notes could make all the difference in receiving prompt reimbursement for your claims.

Why? Coding guidelines require you to code to the highest level of specificity. Distin-guishing between these two quite different notes will help you to select the right code and safeguard your reimbursement.

NOS or "not otherwise specified" or "unspecified" may not seem all that different from NEC or "not elsewhere classifiable" or "other specified," but these notes actually have very different meanings.

NEC indicates that the condition described by the doctor is more specific than the available diagnosis codes -- there is no separate code for the condition even though the diagnosis is specific, says Carol Spencer, RHIA, manager of professional practice resource with the American Health Information Management Association (AHIMA) in Chicago.

NOS, on the other hand, means "unspecified." In this case, the doctor's statement doesn't permit you to get any more specific, Spencer explains.

Red flag: If you're assigning a lot of unspecified codes (which often end in 9), you may have a documentation problem, Spencer warns. Remember, ICD-9 diagnosis codes are used not only to support reimbursement, but also to track severity of the illness, and to analyze code sets -- so the more specific code, the better. For example, 707.14 (Ulcer of heel and midfoot) offers better detail than 707.00 (Decubitus ulcer of unspecified site).

You might see NEC or "not elsewhere classifiable" in the alphabetic index or in the tabular list. When you see this note in the alphabetic index, it indicates that a specific code isn't available for the condition you are coding, and directs you to use the appropriate "other specified" code located in the tabular list, according to the Centers for Medicare & Medicaid Services coding guidelines. These codes, which usually include a fourth digit "8" or a fifth digit "9," are "for use when the information in the medical record provides detail for which a specific code does not exist," CMS coding guidelines explain.

NOS or "not otherwise specified" codes are "for use when the information in the medical record is insufficient to assign a more specific code," CMS guidelines indicate. You'll notice that these codes usually have a fourth digit "9" or fifth digit "0."

Using an unspecified code could put your claim at risk. "The more specific codes are always more apt to be paid than a non-specific code," says Pat Trela, RHIA of PaTrela Consulting in Quincy, MA. When-ever there is a specific code to describe exactly what is going on with your patient, you should use it.

But if you just don't have the specificity you need to choose another code, sometimes an unspecified code is your only option.

Example: If you have a vague diagnostic statement like arteriosclerosis, reporting 440.9 (Arterio-sclerotic vascular disease NOS) may be the way to go. But if you have a more specific diagnosis, such as arteriosclerotic heart disease with left ventricular failure, you should use the corresponding more specific codes. The more detailed diagnosis allows you to report 429.2 (Cardiovascular disease, unspecified) and 428.1 (Left heart failure). With the first example, you don't even know what part of the body is affected by the arteriosclerosis, let alone what its results have been. The second example explains that the arteriosclerosis is in the heart and the left heart failure describes the result of the arteriosclerosis.

In some circumstances, you may have a very specific diagnosis, like necrosis of the pelvis, but when you look it up in your ICD-9-CM coding manual, you'll find that there is no exact match.

Example: When you look up necrosis, you find codes for several other bones, and even unspecified code 733.40 (Asceptic necrosis of bone, site unspecified), but no code for necrosis of the pelvis. When the diagnosis is specified, but there's no code for it, you would use the 'other' or 'not elsewhere classified' code, says Trela. In this case, that would be 733.49 (Aseptic necrosis of bone, other).

But you don't always get the level of specificity that you need to assign an "other" code. And to use the "not elsewhere classified" codes when you don't actually have a level of specificity is wrong.

Example: If you have a diagnostic statement of pericardial disease, you should use 423.9 (Unspecified disease of pericardium), not 423.8 (Other specified diseases of pericardium). Coding this diagnosis with 423.8 might be construed as code jamming, because you are assuming a level of specificity that you don't have.