Home Coding Choosing ICD-9 codes for three common inpatient conditions

Choosing ICD-9 codes for three common inpatient conditions

March 2004

Published in the March 2004 issue of Today’s Hospitalist

Related article: New Medicare rules for billing in 2014

While ICD-9-CM coding is key in identifying the symptoms and conditions treated during patient care, too many physicians don’t take full advantage of ICD-9 codes. As a result, physicians and their institutions often don’t get the credit they deserve for treating complex illnesses.

Treat a patient for something as simple as hypertension, for example, and you can report a number of factors, all of which will help to truly reflect the patient’s severity of illness and the physician’s effort treating that patient. You can specify whether the condition was stable, whether it was malignant, and whether there were any associated heart or
renal problems.

Neglect to provide this level of detail, however, and your coding department will likely have to revert to unspecified ICD-9 codes. The ICD-9 manual lists several types of unspecified codes, including “unspecified,” “NEC” (not elsewhere classifiable,” and “NOS” (not otherwise specified).

Providing the most specific ICD-9 codes is important for several reasons. For one, many hospitals use these codes to keep track of their utilization management. ICD-9 codes are also used by public health officials to track epidemics, create census reports, and for medical research purposes.

While ICD-9 codes are updated every year, the reality is that it’s all too easy for both physicians and coders to become complacent and use a narrow range of codes with which they are familiar. The good news is that when physicians provide enough detail in the medical record, coders can avoid using these codes altogether. Ultimately this is best for reimbursement, because more payers are deciding to steer clear from unspecified codes.

Here is the range of ICD-9 codes for three diagnoses that are the bread and butter of hospitalists “hypertension, diabetes mellitus and myocardial infarction “and some tips on how to report specific codes.


The ICD-9 manual lists two basic types of hypertension. Benign hypertension is defined as generally asymptomatic and stable, while malignant hypertension can include symptoms such as headache or vision problems. In addition, malignant hypertension starts with abrupt onset and often ends with renal failure and/or CVA.

For a sample of the ICD-9 codes available to report hypertension, see “ICD -9 codes to report hypertension care”, below. This list is designed to give you an idea of the range of options you can report when coding your care of a hypertensive patient.

In the third column, you’ll note a category of “unspecified” codes. If you don’t give your coders enough information in the medical record, they’ll be forced to report this code. Both you and your hospital won’t receive your due credit for taking care of a sicker patient.

icd-9 codes

Diabetes mellitus

At the most basic level, ICD-9 codes require you to specify whether your diabetic patient has type 1 or type 2 diabetes. You can also report any related manifestations or complications.

Here is a list of some of the specific codes you can report when treating diabetic patients:Complications (to determine fifth digit, see type and status categories, below):

  • DM, without mention of complication (250.0x)
  • DM, with ketoacidosis (250.1x)
  • DM, with hyposmolarity (250.2x)
  • DM, with other coma (250.3x)
  • DM, with renal manifestations (250.4x)
  • DM, with ophthalmic manifestations (250.5x)
  • DM, with neurological manifestations (250.6x)
  • DM, with peripheral circulatory disorders (250.7x)
  • DM, with other manifestations (250.8x)
  • DM, with unspecified complication (250.9x)

Type and status (to determine first four digits, see list of complications, above):

  • Type II, non-insulin dependent, not stated as uncontrolled (xxx.x0)
  • Type I, insulin dependent, not stated as uncontrolled (xxx.x1)
  • Type II, non-insulin dependent, uncontrolled (xxx.x2)
  • Type I, insulin dependent, uncontrolled (xxx.x3)

Because the coder can make no assumptions when reporting ICD-9 codes, any related problems must be clearly stated in the record. When the medical record doesn’t contain this type of information, the coder must default to ICD-9 250.00.

This code indicates only diabetes mellitus with no mention of complication, not stated as uncontrolled. This code is also known as diabetes mellitus not otherwise specified (NOS).

Myocardial infarction

In order to properly identify what code to report when treating a patient who has experienced a myocardial infarction, you need to document and report the location and episode of care. Here are your choices for all locations:

Location (to determine fifth digit, see episode of care, below):

  • anterolateral wall (410.0x)
  • other anterior wall (410.1x)
  • inferolateral wall (410.2x)
  • inferoposterior wall (410.3x)
  • other inferior wall (410.4x)
  • other lateral wall (410.5x)
  • true posterior wall (410.6x)
  • subendocardial (410.7x)
  • other unspecified site (410.8x)
  • unspecified site (410.9x)

Episode of care (to determine first four digits, see location list, above):

  • episode of care unspecified (xxx.x0)
  • initial episode of care (xxx.x1)
  • subsequent episode of care (xxx.x2)

Most commonly, the medical record will not provide information about the site or episode of care. Once again, the coder must use myocardial infarction of unspecified site, with unspecified episode ICD-9 410.90.

Tamra McLain can be reached through e-mail.