2027 ICD-10-CM Diagnosis Code Z15.1Genetic susceptibility to epilepsy and neurodevelopmental disorders

ICD-10-CM Codes›Z00–Z99›Z14-Z15›Z15

ICD-10-CM Z15.1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z15.1 is a billable ICD-10-CM diagnosis code for genetic susceptibility to epilepsy and neurodevelopmental disorders. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 951. The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Genetic susceptibility to disease.

Code Identity

ICD-10-CM Code
Z15.1
Billable Status
Yes — Valid for Submission
Code Describes
Genetic susceptibility to epilepsy and neurodevelopmental disorders
Short Description
Genetic susceptibility to epi and neurodevelopmental disord
Parent Code
Z15
Genetic susceptibility to disease

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ14-Z15Genetic carrier and genetic susceptibility to disease
CategoryZ15Genetic susceptibility to disease
This CodeZ15.1Genetic susceptibility to epilepsy and neurodevelopmental disorders

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z15.1.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Present on Admission (POA)Billing

Z15.1 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Genetic carrier and genetic susceptibility to disease (Z14-Z15).

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z15.1: its own notes plus those printed at Z15 and Chapter 21. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Z15 Genetic susceptibility to disease applies to 14 codes
  • confirmed abnormal gene

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Z15 Genetic susceptibility to disease applies to 14 codes
  • chromosomal anomalies (Q90-Q99)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Z15 Genetic susceptibility to disease applies to 14 codes
  • code, if applicable, for any associated family history of the disease (Z80-Z84)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

  • if applicable, related disorders such as:
  • developmental and epileptic encephalopathy (G93.45)
  • developmental disorder of speech and language (F80.-)
  • developmental disorders of scholastic skills (F81.-)
  • epilepsy, by specific type (G40.-)
  • intellectual disabilities (F70-F79)
  • other neurodevelopmental disorder (F88)
  • pervasive developmental disorders (F84.-)

Notes

General instructions on how these codes are used.

From Chapter 21 (Z00-Z99) Factors influencing health status and contact with health services applies to 1,425 codes
  • Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
  • (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
  • (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Z15.1, its category, or a range that includes it.

Use Additional Code 1

These codes say to use an additional code from the note, and Z15.1 is one of the codes named.

  • Z40.0 Encounter for prophylactic surgery for risk factors related to malignant neoplasms
    code to identify risk factor, such as genetic susceptibility to malignant neoplasm Z15.- names Z15.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR FAC029
Genetic susceptibility to disease
Default principal diagnosis: inpatient No · outpatient No

Code History & ChangesHistory

Replacement Z15.1 replaces the following previously assigned code(s):

  • Z15.89 - Genetic susceptibility to other disease
FY 2025AddedAdded to the ICD-10-CM code setEffective October 1, 2024.
FY 2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Z15.1Overview

What is the ICD-10 code for genetic susceptibility to epilepsy and neurodevelopmental disorders?

The ICD-10-CM code for genetic susceptibility to epilepsy and neurodevelopmental disorders is Z15.1 (sometimes written as Z151). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Z15.1 (Genetic susceptibility to disease) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report genetic susceptibility to epilepsy and neurodevelopmental disorders on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Z15.1 group to?

On inpatient claims, genetic susceptibility to epilepsy and neurodevelopmental disorders maps to MS-DRG 951 (other Factors Influencing Health Status), which carries a relative weight of 0.5574. Higher weights mean higher Medicare reimbursement.

Can Z15.1 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because genetic susceptibility to epilepsy and neurodevelopmental disorders describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z15.1 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for genetic susceptibility to epilepsy and neurodevelopmental disorders on inpatient claims. The code appears in the Genetic carrier and genetic susceptibility to disease (Z14-Z15) range of the CMS exempt list.