2027 ICD-10-CM Diagnosis Code Z55.0Illiteracy and low-level literacy

ICD-10-CM Codes›Z00–Z99›Z55-Z65›Z55

ICD-10-CM Z55.0
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z55.0 is a billable ICD-10-CM diagnosis code for illiteracy and low-level literacy. 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 educational problem. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Socioeconomic/psychosocial factors.

Code Identity

ICD-10-CM Code
Z55.0
Billable Status
Yes — Valid for Submission
Code Describes
Illiteracy and low-level literacy
Short Description
Illiteracy and low-level literacy
Same as the full description in the CMS dataset.
Parent Code
Z55
Problems related to education and literacy

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ55-Z65Persons with potential health hazards related to socioeconomic and psychosocial circumstances
CategoryZ55Problems related to education and literacy
This CodeZ55.0Illiteracy and low-level literacy

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z55.0.

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

Z55.0 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 socioeconomic and psychosocial circumstances (Z55-Z65).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Educational problem
  • Finding related to ability to read
  • Finding related to literacy level
  • Illiteracy
  • Illiterate literacy level
  • Literacy problems
  • Low-level literacy
  • Unable to read

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z55.0: its own notes plus those printed at Z55 and Chapter 21. A note printed at a category, block or chapter applies to every code under it.

Excludes1

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

From Z55 Problems related to education and literacy applies to 9 codes
  • disorders of psychological development (F80-F89)

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.

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 FAC019
Socioeconomic/psychosocial factors
Default principal diagnosis: inpatient No · outpatient No

Convert Z55.0 to ICD-9-CMHistory

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

ICD-9-CM
V62.3 Educational circumstance
Approximate The match is approximate rather than exact.

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 Z55.0Overview

What is the ICD-10 code for illiteracy and low-level literacy?

The ICD-10-CM code for illiteracy and low-level literacy is Z55.0 (sometimes written as Z550). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Z55.0 (Problems related to education and literacy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report illiteracy and low-level literacy on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Z55.0 group to?

On inpatient claims, illiteracy and low-level literacy 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 Z55.0 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because illiteracy and low-level literacy describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z55.0 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 illiteracy and low-level literacy on inpatient claims. The code appears in the Persons with potential health hazards related to socioeconomic and psychosocial circumstances (Z55-Z65) range of the CMS exempt list.