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ICD-10-CM 7th Character Extension

Although the fundamental guidelines for coding remain essentially the same, the ICD-10-CM code set has been greatly expanded. The number of codes has risen dramatically from 13,000 codes in ICD-9-CM to over 68,000 codes in the new code set. ICD-10-CM has some new features that provide greater specificity compared to ICD-9-CM. In part, this specificity is accomplished by assigning the 7th character, also referred to as the 7th character extension, to some codes in ICD-10-CM. The 7th character is one of the most significant differences between the two code sets.

Characteristics of ICD-10-CM codes: - Alphanumeric and up to 7 characters in length - The first character is always alphabetic - The second character is always numeric - The remaining five digits are a combination of alphabetic and numeric - All codes require a decimal after the third character - If laterality is required in a code, it must be included to make the code valid - Characters 1-3 indicate the category of diagnosis - Characters 4-6 indicate etiology, anatomic site, severity, and other clinical details - The 7th character indicates the type of encounter, type of fracture, or some other vital information

The 7th digit was added to some codes in ICD-10-CM to provide additional information. The details that are captured by this 7th character extension were not previously recorded when the ICD-9-CM codes were in use. ICD-9-CM codes were 3-5 digit codes while the ICD-10-CM codes can be up to 7 characters long. There can be no direct one-to-one mapping between the new and old code sets since the 7th character did not exist in ICD-9-CM.

Related Link: ICD-9 to ICD-10 Coverter

The Tabular List of each chapter in ICD-10-CM clearly states whether the 7th character is needed. 7th character extensions are primarily used in Chapters 13, 15, 19, and 20 and are designated with a letter. The 7th digit differs from other digits in the ICD-10-CM codes because it captures specific information which was previously not recorded when ICD-9-CM was in use. Most categories in these chapters require a 7th character extension for each applicable code. The 7th character extension must occupy the 7th data field, and if the preceding code has fewer than six characters, a dummy placeholder X is used to fill empty fields so that the 7th character can assume its correct position. Example of a code with dummy placeholders: H40.11X4 - Primary open-angle glaucoma, indeterminate stage.

For injuries, poisonings, and other consequences of external causes covered under Chapter 19, the 7th character extension captures information about the type of clinical encounter. The episode of care is designated by the 7th character and specifies the visit as initial, subsequent, or sequela. In some instances, such as traumatic or open fractures, the 7th character extension provides further specific information about the diagnosis.

For example, if a patient is seen for physical therapy and rehabilitation of a strained right Achilles tendon, the appropriate 7-digit ICD-10-CM code will be S86.011D:

• S86: Injury of muscle, fascia and tendon at lower leg level
• S86.0: Injury of Achilles tendon
• S86.01: Strain of Achilles tendon
• S86.011: Strain of right Achilles tendon
• S86.011D: Strain of right Achilles tendon, subsequent encounter

Pregnanct and 7th Character Extensions

For pregnancy, childbirth, and puerperium covered under Chapter 15, the 7th character extension captures information about the fetus. Certain complications of pregnancy are specified by the 7th character, and in the case of multiple gestations, the 7th character helps to distinguish which fetus(es) are affected by the diagnosis being coded.

Initial Encounters, Subsequent Encounters, and Sequela

Initial Encounters, Subsequent Encounters, and Sequela -- not to be confused with "Encounters of The Third Kind."

When the patient is receiving active treatment for an injury, the initial encounter "A" seventh character extension is used in the 7th data field of the code. "Initial encounter" can be misleading; in fact, it does not necessarily have to be the patient's first visit. As long as the patient is receiving active treatment, the 7th character value will remain "A." This includes surgical treatment, emergency department encounters, and initial assessment and treatment by a physician.

The 7th character value of A can be assigned to more than one claim. For example, if a patient undergoes an initial evaluation by an ED physician, a radiologist, and a cardiologist, then the 7th character value "A" for the initial encounter will be used by all three physicians. As long as the patient is progressing, the treatment is considered active and 7th character extension "A" is applicable.

When a patient has already received treatment for an injury before and is receiving routine care during the healing or recovery phase, then the subsequent encounter "D" extension is applicable. This means that maximum medical improvement has been reached and the patient has ceased to progress, but treatment is continuing to facilitate healing and recovery. Examples for such encounters include removal of fixation devices, change of cast, followup care, or medication adjustments.

When complications or other sequelae arise as a direct consequence of an injury, the sequela extension "S" is applicable as the seventh character extension. Examples for this type of encounter would include evaluation of scars or joint contractures resulting from an injury.

7th Character for Fractures

The 7th character extension in ICD-10-CM codes for fractures provides even greater specificity including detailed information about open versus closed fracture, routine versus delayed healing, and malunion or nonunion. The Gustilo classification divides fractures into classes based on the mechanism of injury, extent of soft tissue damage, and degree of bone injury or involvement. The 7th character extension for fractures in ICD-10-CM captures information about the corresponding Gustilo classification. There is no 7th character for "not otherwise specified." If a fracture is not specified as open or closed, it is assumed to be closed. The physician should provide detailed information about the open/closed nature of the fracture and the appropriate Gustilo classification to allow the diagnosis to be correctly coded.

In the following example, more detailed information is added to the code with each additional character, but only the last code is reportable:

• S52: Fracture of forearm
• S52.0: Fracture of upper end of ulna
• S52.02: Fracture of olecranon process without intra-articular extension of ulna
• S52.021: Displaced fracture of olecranon process without intra-articular extension of right ulna
• S52.011D: Displaced fracture of olecranon process without intra-articular extension of right ulna, subsequent encounter for closed fracture with routine healing

Without the 7th digit, the ICD-9-CM code set did not capture the degree of specificity that can now be recorded with ICD-10-CM. The older code set did not provide a mechanism to capture the details that are now recorded by the 7th character. This extra level of detail can only be recorded with the 7th character extension in ICD-10-CM.

The 7th character extension in ICD-10-CM is not optional. If the 7th character is not used when required, it will lead to a rejection of the claim even in the ICD-10 grace period. The 7th character extension must always be used in the 7th position, with the use of dummy X placeholders in empty slots for codes that are less than 6 characters long. For injuries, there are only three variations of the 7th character extension - A, D, or S - used to designate episode of care. For fractures, there are several variations of the 7th character extension - A, B, C, D, E, F, G, H, J, K, M, N, P, Q, R, or S - used to specify details about the fracture - open/closed, routine/delayed healing, malunion, nonunion, and the corresponding Gustilo classification.