{"id":16155,"date":"2023-01-03T07:49:00","date_gmt":"2023-01-03T07:49:00","guid":{"rendered":"https:\/\/www.medicalbillersandcoders.com\/blog\/?p=16155"},"modified":"2026-06-01T14:31:08","modified_gmt":"2026-06-01T09:01:08","slug":"general-coding-guidelines-for-icd-10-cm","status":"publish","type":"post","link":"https:\/\/www.medicalbillersandcoders.com\/blog\/general-coding-guidelines-for-icd-10-cm\/","title":{"rendered":"General Coding Guidelines for ICD-10-CM"},"content":{"rendered":"

ICD-10-CM Basics<\/strong><\/h2>\r\n

Selecting accurate diagnosis codes using ICD-10-CM is challenging due to the availability of more than 68,000 codes. In this blog, we shared general coding guidelines for ICD-10-CM, which will help you select accurate diagnosis codes. Before we proceed with coding guidelines, you\u2019ll need access to two lists in ICD-10 CM: the Alphabetical Index of diagnostic terms and the Tabular List of ICD-10 codes.<\/span><\/p>\r\n

The Alphabetical Index of diagnostic terms lists thousands of \u2018main terms\u2019 alphabetically. Under each of those main terms, there is often a sub-list of more detailed terms; for instance, \u2018Cataract\u2019 has a sub-list of 84 terms. The Tabular List of ICD-10 codes is organized alphanumerically from A00.0 to Z99.89. It is divided into chapters based on body parts or conditions.<\/span><\/p>\r\n\r\n\r\n\r\n\r\n
Wound Care Billing<\/a><\/td>\r\nOb-Gyn Billing<\/a><\/td>\r\nDermatology Billing<\/a><\/td>\r\n<\/tr>\r\n
Family Practice Billing<\/a><\/td>\r\nOrthopedic Billing<\/a><\/td>\r\nOptometry Billing<\/a><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n

General Coding Guidelines for ICD-10-CM<\/strong><\/h2>\r\n

Locating a code in the ICD-10-CM\u00a0<\/strong><\/h3>\r\n

To select a code in the classification corresponding to a diagnosis or reason for a visit documented in a medical record, locate the term in the Alphabetic Index and then verify the code in the Tabular List. <\/span><\/p>\r\n

Read and be guided by instructional notations in the Alphabetic Index and the Tabular List. It is essential to use both the Alphabetic Index and Tabular List when locating and assigning a code.<\/span><\/p>\r\n

The Alphabetic Index does not always provide the complete code. The entire code, including laterality and any applicable 7th character, can only be selected<\/span>\u00a0in the Tabular List. <\/span><\/p>\r\n

A dash (-) at the end of an Alphabetic Index entry indicates that additional characters are required. Even if a dash is not included in the Alphabetic Index entry, referring to the Tabular List is necessary to verify that no 7th character is required.<\/span><\/p>\r\n

Level of Detail in Coding\u00a0<\/strong><\/h3>\r\n

Diagnosis codes are to be used and reported at the highest number of characters available and to the highest level of specificity documented in the medical record. ICD-10-CM diagnosis codes are composed of 3, 4, 5, 6, or 7 characters. <\/span><\/p>\r\n

Codes with three characters are included in ICD-10-CM as the heading of a category of codes that may be further subdivided by using fourth, fifth, or sixth characters, which provide greater detail. <\/span><\/p>\r\n

A three-character code will be used only if not further subdivided. If applicable, a code is invalid if it has not been coded to the total number of characters required for that code, including the 7th character<\/span>.<\/span><\/p>\r\n

Multiple Coding for a Single Condition\u00a0<\/strong><\/h3>\r\n

In addition to the etiology\/manifestation convention that requires two codes to describe a single condition that affects multiple body systems entirely, other single conditions also need more than one code. \u2018Use additional code\u2019 notes are found in the Tabular List for codes not part of an etiology\/manifestation pair where a secondary code is helpful in fully describing a condition. <\/span><\/p>\r\n

The sequencing rule is the same as the etiology\/manifestation pair. ‘ Use additional code\u2019 indicates that a secondary code should be added if known.\u00a0<\/span><\/p>\r\n

Combination Code\u00a0<\/strong><\/h3>\r\n

A combination code is a single code used to classify two diagnoses: a diagnosis with an associated secondary process (manifestation) or an associated complication. Combination codes are identified by referring to sub-term entries in the alphabetic index and reading the inclusion and exclusion notes on the tabular list. <\/span><\/p>\r\n

Assign only the combination code when that code fully identifies the diagnostic conditions involved or when the Alphabetic Index directs. <\/span>Multiple coding should not be used when the classification provides a combination code that identifies all the elements documented in the diagnosis. <\/span><\/p>\r\n

When the combination code lacks specificity in describing the manifestation or complication, an additional code should be used as a secondary code.<\/span><\/p>\r\n

Sequela (Late Effects)\u00a0<\/strong><\/h3>\r\n

A sequela is a residual effect (condition produced) after the acute phase of an illness or injury has terminated. There is no time limit on when a sequela code can be used. The residual may be apparent early, such as in cerebral infarction, or it may occur months or years later due to a previous injury.<\/span><\/p>\r\n

Examples of sequela include scar formation resulting from a burn, deviated septum due to a nasal fracture, and infertility due to tubal occlusion from old tuberculosis. Coding of sequela generally requires two codes sequenced in the following order: the condition or nature of the sequela is sequenced first. The sequela code is sequenced second.<\/span><\/p>\r\n

Use of Sign\/Symptom\/Unspecified Codes\u00a0<\/strong><\/h3>\r\n

Sign\/symptom and \u2018unspecified\u2019 codes have acceptable, even necessary, uses. While specific diagnosis codes should be reported when supported by the available medical record documentation and clinical knowledge of the patient\u2019s health condition, there are instances when signs\/symptoms or unspecified codes are the best choices for accurately reflecting the healthcare encounter. Each healthcare encounter should be coded to the level of certainty known for that encounter.\u00a0<\/span><\/p>\r\n

Impending or Threatened Condition\u00a0<\/strong><\/h2>\r\n

Code any condition described at the time of discharge as \u2018impending\u2019 or \u2018threatened\u2019 as follows:\u00a0<\/strong><\/p>\r\n