2027 ICD-10-CM Diagnosis Code Z86.61Personal history of infections of the central nervous system

ICD-10-CM Codes›Z00–Z99›Z77-Z99›Z86

ICD-10-CM Z86.61
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z86.61 is a billable ICD-10-CM diagnosis code for personal history of infections of the central nervous system. 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. Coders also document this condition as H/O: encephalitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Personal history of other disease.

Code Identity

ICD-10-CM Code
Z86.61
Billable Status
Yes — Valid for Submission
Code Describes
Personal history of infections of the central nervous system
Short Description
Personal history of infections of the central nervous system
Same as the full description in the CMS dataset.
Parent Code
Z86.6
Personal history of diseases of the nervous system and sense organs

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ77-Z99Persons with potential health hazards related to family and personal history and certain conditions influencing health status
CategoryZ86Personal history of certain other diseases
This CodeZ86.61Personal history of infections of the central nervous system

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z86.61.

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

Z86.61 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Persons with potential health hazards related to family and personal history and certain conditions influencing health status (Z77-Z99).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • H/O: encephalitis
  • H/O: meningitis
  • History of infectious disease of central nervous system
  • History of listeria meningitis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z86.61: its own notes plus those printed at Z86, block Z77-Z99, and Chapter 21. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Personal history of encephalitis
  • Personal history of meningitis

Code First

The underlying condition named in the note is sequenced before this code.

From Z86 Personal history of certain other diseases applies to 40 codes
  • any follow-up examination after treatment (Z09)

Code Also

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

From Block Z77-Z99 Persons with potential health hazards related to family and personal history and certain conditions influencing health status applies to 567 codes
  • any follow-up examination (Z08-Z09)

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 Z86.61, its category, or a range that includes it.

Use Additional Code 1

These codes say to use an additional code from the note, and Z86.61 is one of the codes named.

  • Z09 Encounter for follow-up examination after completed treatment for conditions other than malignant neoplasm
    code to identify any applicable history of disease code (Z86.-, Z87.-) names Z86.-, 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 FAC030
Personal history of other disease
Default principal diagnosis: inpatient No · outpatient Yes

Patient EducationClinical

Encephalitis

Encephalitis is inflammation (swelling) of the brain. It can happen when an infection or medical condition that affects the brain activates your immune system. The inflammation can cause a wide range of symptoms. In extreme cases, it can lead to brain damage, stroke, or even death.

The full article covers:

  • What is encephalitis?
  • What causes encephalitis?
  • Who is more likely to get encephalitis?
  • What are the symptoms of encephalitis?
  • How is encephalitis diagnosed?
  • What are the treatments for encephalitis?
  • Can encephalitis be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Z86.61 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
V12.42 Personl hx infection CNS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Z86.61Overview

What is the ICD-10 code for personal history of infections of the central nervous system?

The ICD-10-CM code for personal history of infections of the central nervous system is Z86.61 (sometimes written as Z8661). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Z86.61 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report personal history of infections of the central nervous system on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Z86.61 group to?

On inpatient claims, personal history of infections of the central nervous system 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 Z86.61 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because personal history of infections of the central nervous system describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z86.61 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 personal history of infections of the central nervous system on inpatient claims. The code appears in the Persons with potential health hazards related to family and personal history and certain conditions influencing health status (Z77-Z99) range of the CMS exempt list.