Pair These ICD-10 2018 Official Guideline Updates With Their Code Set Counterparts

ICD-10 Official Guidelines

The ICD-10-CM 2018 Official Guidelines are out and ready for review. When you check through the new OGs for changes, take special note of these updates that line up with 2018 code set revisions.

Look at Level to Choose ‘In Remission’ Code

When you start to apply new codes for substance abuse in remission (you’ll find them in categories F10-F19), keep in mind this new paragraph in Section I.C.5.b.1:

Mild substance use disorders in early or sustained remission are classified to the appropriate codes for substance abuse in remission, and moderate or severe substance use disorders in early or sustained remission are classified to the appropriate codes for substance dependence in remission.

Be Ready for New Blindness Codes

ICD-10-CM 2018 introduces about 50 new subcategories and reportable codes for low vision and blindness. The changes help you report the status of both eyes in a single code. Follow these rules from Section I.C.7.b when documentation is less than ideal:

If “blindness” or “low vision” of both eyes is documented but the visual impairment category is not documented, assign code H54.3, Unqualified visual loss, both eyes. If “blindness” or “low vision” in one eye is documented but the visual impairment category is not documented, assign a code from H54.6-, Unqualified visual loss, one eye. If “blindness” or “visual loss” is documented without any information about whether one or both eyes are affected, assign code H54.7, Unspecified visual loss.

Keep Type in Mind for MI OGs

The OGs have long been important for understanding myocardial infarction (MI) coding. Things get a little more interesting this year because the OGs have to take into account a new coding structure for MI. Existing codes I21.0- to I21.4 will apply to type 1 MIs in the new code set. For MI NOS, you’ll have I21.9 (Acute myocardial infarction, unspecified). For type 2 MI, you’ll choose I21. A1 (Myocardial infarction type 2), and for types 3-5 you’ll use I21.A9 (Other myocardial infarction type).

If you code MIs, be sure to read all of Section I.C.9.e because there are revisions sprinkled throughout showing that the OGs you’re accustomed to using will apply to type 1 MI. For subsequent MI, don’t miss this added paragraph:

Do not assign code I22 for subsequent myocardial infarctions other than type 1 or unspecified. For subsequent type 2 AMI assign only code I21.A1. For subsequent type 4 or type 5 AMI, assign only code I21.A9.

To help you get to know the new type 2 code, take note of this added paragraph:

Type 2 myocardial infarction, and myocardial infarction due to demand ischemia or secondary to ischemic balance, is assigned to code I21.A1, Myocardial infarction type 2[,] with a code for the underlying cause. Do not assign code I24.8, Other forms of acute ischemic heart disease[,] for the demand ischemia. Sequencing of type 2 AMI or the underlying cause is dependent on the circumstances of admission. When a type 2 AMI code is described as NSTEMI or STEMI, only assign code I21.A1. Codes I21.01-I21.4 should only be assigned for type 1 AMIs.

Put Your Knowledge to Work for Non-Pressure Ulcers

ICD-10 2018 adds 72 new codes for non-pressure chronic ulcers in L97.- and L98.-, bulking up your already existing options. As you get to know the new codes, spend some time on the OGs that have been added, too. If you know the OGs for pressure ulcers, you’ve got a good head start on knowing the new OGs in Section I.C.12.b for non-pressure chronic ulcers. To sum up:

  • Don’t assign a code for a non-pressure ulcer if documentation states the ulcer was healed when the patient was admitted
  • Assign a code for “healing” non-pressure ulcers based on documentation of severity
  • If severity progresses during admission, assign one code for level at admission and one code for the highest level during the stay.

What About You?

Which ICD-10-CM 2018 guidelines will change the way you code? Do you check these guidelines before coding throughout the year?


Deborah works on a wide range of TCI SuperCoder projects, researching and writing about coding, as well as assisting with data updates and tool development for our online coding solutions. Since joining TCI in 2004, she’s covered the ins and outs of coding for radiology, cardiology, oncology and hematology, orthopedics, audiology, and more.

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