Medical coding is the assignment of numerical or alphabetical digits and characters to specific diagnostic and procedural phrases. Coding like any other language needs to be translated to be understood, and each combination of numbers or of numbers and letters represents a diagnostic or procedural phrase. The ICD classification system was designed to compile and present statistical data on morbidity, the rate or frequency of disease and mortality, the rate or frequency of deaths. ICD-CM9, an abbreviation for the international classification of diseases, ninth revision, clinical modification, is an arrangement of classes or groups of diagnoses and procedures by systematic division (Bowie& Schaffer, 2010)

Four steps necessary to establish a proper ICD-9-CM code:

When using the ICD-9-CM codes, there are four main steps that are followed to ensure that the code is an accurate description of the diagnosis. They include:

1. Identifying the reason for the visit (e.g. sign, symptom, diagnosis, condition to be coded). Physicians describe the patient's condition using terminology that includes specific diagnoses as well as symptoms, problems or reasons for the encounter.

2. Consulting the Alphabetic Index, Volume 2, before turning to the Tabular List. The most critical rule is to begin a code search in the index.
3. Locating the main entry term. The Alphabetic Index is arranged by condition. Conditions may be expressed as nouns, adjectives and eponyms.
4. Reading and interpreting any notes listed with the main term. Notes are identified using italicized type.

Although these are the major steps involved for proper coding, there are other sub stages followed thereafter before the final coding is made (American Medical Association, 2005).