New Uses of the 7th Character in ICD-10-CM Coding

A review of changes that take effect this year.

By Riva Lee Asbell

In the March 2016 issue of Retina Today, I delved into the preliminary coding quandaries relating to using the 7th character with the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM).1 In the 2017 version of that book of diagnosis codes, several new uses have been introduced that pertain specifically to retina coding.2 It is imperative to incorporate these changes in your coding, lest claim denials increase.

There are more than 60 new codes requiring the 7th character in Chapter 4 of the 2017 ICD-10-CM codebook, which contains many of the new codes involving the levels of diabetic retinopathy and concurrent diagnoses: for example, E11.331- Type 2 diabetes mellitus with mild nonproliferative diabetic retinopathy with macular edema. Note that in this article the hyphen (-) at the end of a series of characters indicates that another character is needed. Perusing the ICD-10-CM book for E11.331- reveals that a 7th character must be used to indicate laterality. Chapter 7 includes different kinds of 7th character mandates.

This article explains new uses of the 7th character for 2017.


The length of ICD-10-CM diagnosis codes can range from four to seven characters; however, instructions indicate that when a 7th character is to be used it must be positioned as the 7th character. If a code has less than six characters, then one or more placeholders must be inserted before the 7th character.

Specific instructions in ICD-10-CM state that certain categories have applicable 7th character extensions. In these cases, the 7th character extension is required for all codes within the category, or as otherwise instructed in the tabular list notations. 7th character extensions must always be the last character in the data field. If a code is not a full six characters in length, a dummy placeholder X must be used to fill the empty characters when a 7th character extension is required.2

There are many different sets of 7th characters. Some 7th characters are specialized, and some are more generalized. Types discussed here that are pertinent for retina coding include laterality, disease severity (7th character indicates accompanying clinical diagnosis), and stages for nonexudative and exudative age-related macular degeneration (AMD). The reader will encounter examples of each in this article. In general, do not use unspecified diagnosis codes when either the diagnosis or the chart documentation provides enough information to assign a specific code.


Laterality defines the site of a specific diagnosis. For eyes, the laterality numerical digit indicates right eye, left eye, bilateral, or unspecified. Unspecified means it is not specified in the chart. It is the physicians responsibility to provide the anatomic site in the chart documentation. Specifying laterality became mandatory for certain codes on October 1, 2016.

The box below appears in Chapter 4, with all of the diabetes mellitus and ocular complications codes (ie, E09.32, E09.33, E09.34, E09.35, E09.37; E10.32, E10.33, E10.34, E10.35, E10.37; E11.32, E11.33, E11.34, E11.35, E11.37; E13.32, E13.33, E13.34, E13.35, E13.37). The book notes next to each code that a 7th character is required. This box is a sample for E11. All of the codes listed above use the same laterality designations.

One of the following 7th characters is to be assigned in subcategories E11.32, E11.33, E11.34, E11.35, E11.37:

1 right eye

2 left eye

3 bilateral

9 unspecified eye

Example: E11.3541 Type 2 diabetes mellitus with proliferative diabetic retinopathy with combined traction retinal detachment and rhegmatogenous retinal detachment, right eye.

Disease Severity

Central retinal vein occlusion and tributary (branch) retinal vein occlusion both require 7th characters, based on the severity of the problem. The diagnosis at the bottom of each of the boxes below is an example of using the 7th character 2.

H34.81 Central retinal vein occlusion

One of the following 7th characters is to be assigned to codes in subcategory H34.81 to designate the severity of the occlusion:

0 with macular edema

1 with retinal neovascularization

2 stable
old central retinal vein occlusion

Example: H34.8112 Central retinal vein occlusion (old), right eye

H34.83 Tributary (branch) retinal vein occlusion

One of the following 7th characters is to be assigned to codes in subcategory H34.83 to designate the severity of the occlusion:

0 with macular edema

1 with retinal neovascularization

2 stable
old tributary (branch) retinal vein occlusion

Example: H34.8320 Branch venous occlusion with macular edema, left eye

Stages of Disease

For nonexudative and exudative AMD, stages have been added, and these are mandatory to use. Because these conditions are probably the most frequent diagnoses used in a retina practice, it is critical that the physician cite the stage in the chart documentation. Not only will this practice offer support in the event of an audit, but it will also enhance the efficiency of your billing department.

Tip: When you are coding for a disease that is the same in both eyes (and at the same stage), even if you are treating only one eye at the encounter, the bilateral designation (3) should be used rather than just the right or left eye. The Centers for Medicare and Medicaid Services wants the coding performed this way. The laterality will be designated in the CPT code.

H35.31 Nonexudative age-related macular degeneration

One of the following 7th characters is to be assigned to each code in subcategory H35.31 to designate the stage of the disease:

0 stage unspecified

1 early dry stage

2 intermediate dry stage

3 advanced atrophic without subfoveal involvement

advanced dry stage

4 advanced atrophic with subfoveal involvement

Example: H35.3131 Early dry stage macular degeneration, both eyes

H35.32 Exudative age-related macular degeneration

One of the following 7th characters is to be assigned to each code in subcategory H35.32 to designate the stage of the disease:

0 stage unspecified

1 with active choroidal neovascularization

2 with inactive choroidal neovascularization

with involuted or regressed neovascularization

3 with inactive scar

Example: H35.3231 Wet macular degeneration, both eyes, with active choroidal neovascularization. (Note: Even if only the right eye is injected during a given encounter, the bilateral code would be used. Using the RT or LT designation on the CPT code [67028] defines the laterality.)


The March 2016 Retina Today article referred toabove was devoted to the use of A, D, and S as 7thcharacters.1 They are important when selecting diagnosis codes for situations such as removal of foreign bodies, removal of silicone oil (including migrated silicone oil), and malpositioned intraocular lenses. Chapter 19 of the ICD-10-CM contains some important diagnosis codes that are frequently used by retina specialists. They are prefaced by a box like this:

The appropriate 7th character is to be added to each code from category S05.

A initial encounter

D subsequent encounter

S sequela

The box above also applies to codes from category T 85. Both S and T codes are found in Chapter 19. Below are a few of the pertinent categories found in that chapter.

S05.2 Ocular laceration and rupture with prolapse or loss of intraocular tissue

S05.4 Penetrating wound of orbit with or without foreign body

S05.5 Penetrating wound with foreign body of eyeball

S05.6 Penetrating wound without foreign body of eyeball

T85.2 Mechanical complication of intraocular lens

T85.3 Mechanical complication of other ocular prosthetic devices, implants and grafts

Example: S05.32xA Ocular laceration without prolapse or loss of intraocular tissue, left eye (Note: In the S codes, laterality is indicated.)

Example: T85.22xA Displacement of intraocular lens (Note: Use this code for malpositioning.)

Tips for Use

  • The dictum that A is always used when the patient is receiving active treatment is of critical importance. Thus, any time a procedure is being performed, use A because performing a surgical procedure is always considered active treatment.
  • The placeholder x may be lowercase or uppercase.
  • If the diagnosis code chosen requires a 7th character but one is not used, then the code is considered invalid and the claim will be rejected.
  • No laterality is indicated in T codes, but laterality is indicated in S codes.
  • Do not confuse S,sequela, with the word or concept complication. If surgical repair or medical treatment of a complication is performed, it is considered active treatment.

1. Asbell RL. Troubleshooting the 7th character. Retina Today. 2016; 11(2):22-24.

2. ICD-10-CM: The Complete Official Codebook. Chicago, IL: American Medical Association; 2017.

Riva Lee Asbell
• principal, Riva Lee Asbell Associates, in Fort Lauderdale, Fla.
• financial interest: none acknowledged
CPT codes copyright 2015 American Medical Association


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About Retina Today

Retina Today is a publication that delivers the latest research and clinical developments from areas such as medical retina, retinal surgery, vitreous, diabetes, retinal imaging, posterior segment oncology and ocular trauma. Each issue provides insight from well-respected specialists on cutting-edge therapies and surgical techniques that are currently in use and on the horizon.