The "Sixth and Seventh Character" of ICD-10 - What is it?
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Wednesday, December 31, 2014 04:36 PM

By: Jill Foote, Insurance Quality Analyst III

The deadline for ICD-10 has been postponed until October 1, 2015 and the U.S. Department of Health and Human Services (HHS) has indicated that there will be no grace period for ICD-10 implementation. Now is the time to familiarize yourself with the "characters" that make up an ICD-10 code. 

Implementation of ICD-10-CM will provide a much more detailed description of the patient's condition. This new diagnosis coding "language" allows for comorbidities, etiology, causation, complications, manifestations, degree of functional impairment, detailed anatomic site, phase/stage of treatment, lateralization, localization, joint involvement, sequelae, and even age-related conditions. Our present ICD-9 system makes the provider do more work to communicate medical necessity to the payer.

ICD -10 is composed of codes using between 3 and 7 characters. A code meets ICD-10's highest specificity requirements by using all seven characters.  Like ICD-9, ICD-10 codes are invalid if they have not been coded to the highest level of specificity.

We begin by finding the three-character category heading of the code in the tabular list, which is divided by chapters. For example:

Chapter 19 Injury, Poisoning & Other Certain Consequences of External Causes

S33 "Dislocation and Sprain of Joint and Ligaments of Lumbar Spine and Pelvis"

The fourth character indicates the specific body part and helps the code come "alive" as it begins to communicate to the payer a more complete portrait of the patient's condition.  For example:

S33.1xx_ "Subluxation and dislocation of lumbar vertebra"

The fifth character communicates to the payer the level of the subluxation or dislocation.

S33.11x_ "Subluxation and dislocation of L1/L2 lumbar vertebra"

The sixth character communicates to the payer whether or not it is a subluxation or dislocation.

S33.110_ "Subluxation of L1/L2 lumbar vertebra"

S33.111_ "Dislocation of L1/L2 lumbar vertebra"

The seventh character of ICD-10 is often a required character in codes involving musculoskeletal diseases (Chapter 13, M00-M99), and injuries and poisonings (Chapter 19, S00-T88). The purpose of the 7th character is to communicate to the payer the "type of encounter" such as:

initial (A),
subsequent (D), or

sequela (S).

If a code requires a seventh character, you will see it listed with an underscore "_" in the last column of the ICD-10 code, as shown in the prior examples.

An example of the process of coding subluxation with all seven characters:

Chapter 19 Injury, Poisoning & Other Certain Consequences of External Causes

S33 "Dislocation and Sprain of Joint and Ligaments of Lumbar Spine and Pelvis"

S33.1xx_ "Subluxation and dislocation of lumbar vertebra"

S33.11 Subluxation and dislocation of L1/L2 lumbar vertebra

S33.110 Subluxation of L1/L2 lumbar vertebra

S33.110A...... initial encounter

S33.110D...... subsequent encounter

S33.110S...... sequela

The need to become familiar with the details within ICD-10 is critical. The structure is in place, so why not start by making a list of commonly used ICD-9 codes in your practice and find the ICD-10 GEM (General Equivalency Mapping) so you will be ready? 

Once you have found the three-character code that is similar to the ICD-9 code, begin applying the technique of coding to the highest level of specificity. This is performed by further subdividing the layers of differentiation within the diagnosis by use of the fourth through the seventh characters, which follow the decimal, to communicate greater detail.

Understanding the structure of ICD-10 will assist you in developing the accurate and detailed documentation that is necessary for successful ICD-10 coding. 


Source:  http://www.acatoday.org/ICD-10/documents/TheSixthSeventhCharacter.pdf